diff --git a/app/Models/Achievement.php b/app/Models/Achievement.php
new file mode 100644
index 0000000..fa6b645
--- /dev/null
+++ b/app/Models/Achievement.php
@@ -0,0 +1,72 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Collection;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\BelongsToMany;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+/**
+ * @property int                   $id
+ * @property string                $name
+ * @property string                $internal_name
+ * @property string                $short_description
+ * @property string                $long_description
+ * @property string                $icon
+ * @property bool                  $progressive
+ * @property string|null           $difficulty_description
+ * @property int                   $achievement_category_id
+ * @property int                   $achievement_difficulty_id
+ *
+ * @property-read AchievementCategory    $category
+ * @property-read AchievementDifficulty  $difficulty
+ * @property-read Collection<int, UserAchievement> $userAchievements
+ * @property-read Collection<int, User>  $users
+ */
+class Achievement extends Model
+{
+    protected $fillable = [
+        'name',
+        'internal_name',
+        'short_description',
+        'long_description',
+        'icon',
+        'progressive',
+        'difficulty_description',
+        'achievement_category_id',
+        'achievement_difficulty_id',
+    ];
+
+    protected $casts = [
+        'progressive' => 'boolean',
+    ];
+
+    // ---------------------------------------------------------------
+    // Relationships
+    // ---------------------------------------------------------------
+
+    public function category(): BelongsTo
+    {
+        return $this->belongsTo(AchievementCategory::class, 'achievement_category_id');
+    }
+
+    public function difficulty(): BelongsTo
+    {
+        return $this->belongsTo(AchievementDifficulty::class, 'achievement_difficulty_id');
+    }
+
+    public function userAchievements(): HasMany
+    {
+        return $this->hasMany(UserAchievement::class, 'achievement_id');
+    }
+
+    /** Users who have unlocked (or are progressing toward) this achievement. */
+    public function users(): BelongsToMany
+    {
+        return $this->belongsToMany(User::class, 'user_achievements')
+            ->withPivot('progress')
+            ->withTimestamps();
+    }
+}
diff --git a/app/Models/AchievementCategory.php b/app/Models/AchievementCategory.php
new file mode 100644
index 0000000..81ee181
--- /dev/null
+++ b/app/Models/AchievementCategory.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Collection;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+/**
+ * @property int    $id
+ * @property string $internal_name
+ * @property string $name
+ * @property string $description
+ *
+ * @property-read Collection<int, Achievement> $achievements
+ */
+class AchievementCategory extends Model
+{
+    protected $fillable = [
+        'internal_name',
+        'name',
+        'description',
+    ];
+
+    // ---------------------------------------------------------------
+    // Relationships
+    // ---------------------------------------------------------------
+
+    public function achievements(): HasMany
+    {
+        return $this->hasMany(Achievement::class, 'achievement_category_id');
+    }
+}
diff --git a/app/Models/AchievementDifficulty.php b/app/Models/AchievementDifficulty.php
new file mode 100644
index 0000000..be4368e
--- /dev/null
+++ b/app/Models/AchievementDifficulty.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Collection;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+/**
+ * @property int    $id
+ * @property string $internal_name
+ * @property string $name
+ * @property string $description
+ *
+ * @property-read Collection<int, Achievement> $achievements
+ */
+class AchievementDifficulty extends Model
+{
+    protected $fillable = [
+        'internal_name',
+        'name',
+        'description',
+    ];
+
+    // ---------------------------------------------------------------
+    // Relationships
+    // ---------------------------------------------------------------
+
+    public function achievements(): HasMany
+    {
+        return $this->hasMany(Achievement::class, 'achievement_difficulty_id');
+    }
+}
diff --git a/app/Models/Notification.php b/app/Models/Notification.php
new file mode 100644
index 0000000..4ad6353
--- /dev/null
+++ b/app/Models/Notification.php
@@ -0,0 +1,102 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+/**
+ * @property int              $id
+ * @property int              $user_id
+ * @property string           $title
+ * @property string           $body
+ * @property string|null      $url
+ * @property bool             $is_achievement
+ * @property int|null         $achievement_id
+ * @property \Carbon\Carbon|null $read_at
+ * @property \Carbon\Carbon|null $dismissed_at
+ * @property \Carbon\Carbon|null $expires_at
+ *
+ * @property-read User             $user
+ * @property-read Achievement|null $achievement
+ *
+ * @method static Builder unread()
+ * @method static Builder undismissed()
+ * @method static Builder active()
+ * @method static Builder forAchievements()
+ */
+class Notification extends Model
+{
+    protected $fillable = [
+        'user_id',
+        'title',
+        'body',
+        'url',
+        'is_achievement',
+        'achievement_id',
+        'read_at',
+        'expires_at',
+    ];
+
+    protected $casts = [
+        'is_achievement' => 'boolean',
+        'read_at'        => 'datetime',
+        'expires_at'     => 'datetime',
+    ];
+
+    // ---------------------------------------------------------------
+    // Relationships
+    // ---------------------------------------------------------------
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function achievement(): BelongsTo
+    {
+        return $this->belongsTo(Achievement::class);
+    }
+
+    // ---------------------------------------------------------------
+    // Scopes
+    // ---------------------------------------------------------------
+
+    /** Notifications the user hasn't opened yet. */
+    public function scopeUnread(Builder $query): void
+    {
+        $query->whereNull('read_at');
+    }
+
+    /** Not expired (no expiry set, or expiry is in the future). */
+    public function scopeActive(Builder $query): void
+    {
+        $query->where(function (Builder $q) {
+            $q->whereNull('expires_at')
+                ->orWhere('expires_at', '>', now());
+        });
+    }
+
+    /** Only achievement notifications. */
+    public function scopeForAchievements(Builder $query): void
+    {
+        $query->where('is_achievement', true);
+    }
+
+    // ---------------------------------------------------------------
+    // Helpers
+    // ---------------------------------------------------------------
+
+    public function markAsRead(): void
+    {
+        if (! $this->read_at) {
+            $this->update(['read_at' => now()]);
+        }
+    }
+
+    public function isExpired(): bool
+    {
+        return $this->expires_at !== null && $this->expires_at->isPast();
+    }
+}
diff --git a/app/Models/UserAchievement.php b/app/Models/UserAchievement.php
new file mode 100644
index 0000000..e06e3da
--- /dev/null
+++ b/app/Models/UserAchievement.php
@@ -0,0 +1,42 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+/**
+ * @property int      $id
+ * @property int      $user_id
+ * @property int      $achievement_id
+ * @property int|null $progress
+ *
+ * @property-read User        $user
+ * @property-read Achievement $achievement
+ */
+class UserAchievement extends Model
+{
+    protected $fillable = [
+        'user_id',
+        'achievement_id',
+        'progress',
+    ];
+
+    protected $casts = [
+        'progress' => 'integer',
+    ];
+
+    // ---------------------------------------------------------------
+    // Relationships
+    // ---------------------------------------------------------------
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function achievement(): BelongsTo
+    {
+        return $this->belongsTo(Achievement::class);
+    }
+}
diff --git a/database/migrations/2026_04_26_030253_build_achievement_system.php b/database/migrations/2026_04_26_030253_build_achievement_system.php
new file mode 100644
index 0000000..dbc6b76
--- /dev/null
+++ b/database/migrations/2026_04_26_030253_build_achievement_system.php
@@ -0,0 +1,740 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        // ---------------------------------------------------------------
+        // 1. achievement_difficulties
+        // ---------------------------------------------------------------
+        Schema::create('achievement_difficulties', function (Blueprint $table) {
+            $table->id();
+            $table->string('internal_name')->unique();
+            $table->string('name');
+            $table->text('description');
+            $table->timestamps();
+        });
+
+        DB::table('achievement_difficulties')->insert([
+            [
+                'internal_name' => 'easy',
+                'name'          => 'Easy',
+                'description'   => "As easy as booking a flight somewhere new!",
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+            [
+                'internal_name' => 'moderate',
+                'name'          => 'Moderate',
+                'description'   => 'You might have to reroute your flights a little just to get the achievement!',
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+            [
+                'internal_name' => 'hard',
+                'name'          => 'Hard',
+                'description'   => "You'll need to go quite a bit out of the way to get this achievement!",
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+            [
+                'internal_name' => 'expensive',
+                'name'          => 'Expensive',
+                'description'   => 'It might be hard, but it will be easier if you have a lot of money!',
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+            [
+                'internal_name' => 'near_impossible',
+                'name'          => 'Near-Impossible',
+                'description'   => 'You will actively have to try to get this achievement and they may be very few ways to go about it.',
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+            [
+                'internal_name' => 'impossible',
+                'name'          => 'Impossible',
+                'description'   => 'This achievement is impossible to get if you start today, but was previously possible.',
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+        ]);
+
+        // ---------------------------------------------------------------
+        // 2. achievement_categories
+        // ---------------------------------------------------------------
+        Schema::create('achievement_categories', function (Blueprint $table) {
+            $table->id();
+            $table->string('internal_name')->unique();
+            $table->string('name');
+            $table->text('description');
+            $table->timestamps();
+        });
+
+        DB::table('achievement_categories')->insert([
+            [
+                'internal_name' => 'general_flying',
+                'name'          => 'General Flying',
+                'description'   => 'Achievements earned through everyday flying activity.',
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+            [
+                'internal_name' => 'countries_and_continents',
+                'name'          => 'Countries & Continents',
+                'description'   => 'Achievements for visiting countries, regions, and continents.',
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+            [
+                'internal_name' => 'aircraft',
+                'name'          => 'Aircraft',
+                'description'   => 'Achievements related to specific aircraft types and manufacturers.',
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+            [
+                'internal_name' => 'airlines_and_alliances',
+                'name'          => 'Airlines and Alliances',
+                'description'   => 'Achievements focused on airlines and alliances',
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+            [
+                'internal_name' => 'fun_challenges',
+                'name'          => 'Fun Challenges',
+                'description'   => 'Quirky and creative challenges for the adventurous traveller.',
+                'created_at'    => now(),
+                'updated_at'    => now(),
+            ],
+        ]);
+
+        // ---------------------------------------------------------------
+        // 3. Alter achievements — add new columns & foreign keys
+        // ---------------------------------------------------------------
+        Schema::table('achievements', function (Blueprint $table) {
+            // Replace description with split fields
+            $table->string('short_description')->after('internal_name');
+            $table->text('long_description')->after('short_description');
+
+            // Progressive tracking
+            $table->boolean('progressive')->default(false)->after('long_description');
+
+            // Difficulty flavour text specific to this achievement
+            $table->text('difficulty_description')->nullable()->after('progressive');
+
+            // Foreign keys
+            $table->foreignId('achievement_category_id')
+                ->after('difficulty_description')
+                ->constrained('achievement_categories')
+                ->restrictOnDelete();
+
+            $table->foreignId('achievement_difficulty_id')
+                ->after('achievement_category_id')
+                ->constrained('achievement_difficulties')
+                ->restrictOnDelete();
+
+            // Drop the old monolithic description column
+            $table->dropColumn('description');
+        });
+
+        // ---------------------------------------------------------------
+        // 4. Alter user_achievements — add nullable progress column
+        // ---------------------------------------------------------------
+        Schema::table('user_achievements', function (Blueprint $table) {
+            $table->unsignedInteger('progress')->nullable()->after('achievement_id');
+        });
+
+        Schema::create('notifications', function (Blueprint $table) {
+            $table->id();
+
+            $table->foreignId('user_id')
+                ->constrained('users')
+                ->cascadeOnDelete();
+
+            // Content
+            $table->string('title');
+            $table->text('body');
+            $table->string('url')->nullable();
+
+            // Achievement flag & optional link
+            $table->boolean('is_achievement')->default(false);
+            $table->foreignId('achievement_id')
+                ->nullable()
+                ->constrained('achievements')
+                ->nullOnDelete();
+
+            // State
+            $table->timestamp('read_at')->nullable();
+            $table->timestamp('expires_at')->nullable();
+
+            $table->timestamps();
+
+            // Common query patterns
+            $table->index(['user_id', 'read_at']);
+            $table->index('expires_at');
+        });
+
+
+        $this->seedAchievements();
+    }
+
+    private function seedAchievements(): void
+    {
+        $difficulties  = DB::table('achievement_difficulties')->pluck('id', 'internal_name');
+        $categories    = DB::table('achievement_categories')->pluck('id', 'internal_name');
+
+        $easy         = $difficulties['easy'];
+        $moderate     = $difficulties['moderate'];
+        $hard         = $difficulties['hard'];
+        $expensive    = $difficulties['expensive'];
+        $nearImposs   = $difficulties['near_impossible'];
+        $impossible   = $difficulties['impossible'];
+
+        $generalFlying          = $categories['general_flying'];
+        $countriesAndContinents = $categories['countries_and_continents'];
+        $aircraft               = $categories['aircraft'];
+        $airlinesAndAlliances   = $categories['airlines_and_alliances'];
+        $funChallenges          = $categories['fun_challenges'];
+
+        $icon = 'standard_achievement.png';
+        $now  = now();
+
+        $achievements = [
+
+            // -----------------------------------------------------------
+            // General Flying
+            // -----------------------------------------------------------
+            [
+                'internal_name'            => 'general_flying.first_flight',
+                'name'                     => 'Off the Ground',
+                'short_description'        => 'Log your very first flight.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'general_flying.domestic_flight',
+                'name'                     => 'Home Turf',
+                'short_description'        => 'Take a domestic flight.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'general_flying.international_flight',
+                'name'                     => 'Passport Stamp Collector',
+                'short_description'        => 'Take an international flight.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'general_flying.business_class',
+                'name'                     => 'Flatbed Fan',
+                'short_description'        => 'Fly in Business Class.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $expensive,
+            ],
+            [
+                'internal_name'            => 'general_flying.first_class',
+                'name'                     => 'Caviar at 35,000 Feet',
+                'short_description'        => 'Fly in First Class.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $expensive,
+            ],
+            [
+                'internal_name'            => 'general_flying.premium_economy',
+                'name'                     => 'Legroom Lover',
+                'short_description'        => 'Fly in Premium Economy.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $expensive,
+            ],
+            [
+                'internal_name'            => 'general_flying.business_or_first',
+                'name'                     => 'Turn Left',
+                'short_description'        => 'Fly in Business or First Class.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $moderate,
+            ],
+            [
+                'internal_name'            => 'general_flying.fly_private',
+                'name'                     => 'Wheels Up',
+                'short_description'        => 'Fly on a private aircraft.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $expensive,
+            ],
+            [
+                'internal_name'            => 'general_flying.general_aviation',
+                'name'                     => 'Little Plane, Big Sky',
+                'short_description'        => 'Take a general aviation flight.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $moderate,
+            ],
+            [
+                'internal_name'            => 'general_flying.domestic_two_countries',
+                'name'                     => 'Local Explorer',
+                'short_description'        => 'Take domestic flights in two different countries.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $moderate,
+            ],
+            [
+                'internal_name'            => 'general_flying.10_flights',
+                'name'                     => 'Frequent Flyer in Training',
+                'short_description'        => 'Log 10 flights.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => true,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'general_flying.100_flights',
+                'name'                     => 'Century in the Sky',
+                'short_description'        => 'Log 100 flights.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => true,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $moderate,
+            ],
+            [
+                'internal_name'            => 'general_flying.500_flights',
+                'name'                     => 'The 500 Club',
+                'short_description'        => 'Log 500 flights.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => true,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $hard,
+            ],
+            [
+                'internal_name'            => 'general_flying.1000_flights',
+                'name'                     => 'Skybound for Life',
+                'short_description'        => 'Log 1,000 flights.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => true,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $generalFlying,
+                'achievement_difficulty_id'=> $expensive,
+            ],
+
+            // -----------------------------------------------------------
+            // Countries & Continents
+            // -----------------------------------------------------------
+            [
+                'internal_name'            => 'countries_continents.intercontinental',
+                'name'                     => 'Intercontinental',
+                'short_description'        => 'Fly between two different continents.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $countriesAndContinents,
+                'achievement_difficulty_id'=> $moderate,
+            ],
+            [
+                'internal_name'            => 'countries_continents.fly_to_africa',
+                'name'                     => 'Safari Bound',
+                'short_description'        => 'Fly to Africa.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $countriesAndContinents,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'countries_continents.fly_to_asia',
+                'name'                     => 'Orient Express (Air Edition)',
+                'short_description'        => 'Fly to Asia.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $countriesAndContinents,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'countries_continents.fly_to_oceania',
+                'name'                     => "G'Day from 35,000 Feet",
+                'short_description'        => 'Fly to Oceania.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $countriesAndContinents,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'countries_continents.fly_to_antarctica',
+                'name'                     => 'Penguin Spotter',
+                'short_description'        => 'Fly to Antarctica.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => 'Very few commercial or charter services operate to Antarctica, making this extremely difficult to pull off.',
+                'achievement_category_id'  => $countriesAndContinents,
+                'achievement_difficulty_id'=> $expensive,
+            ],
+            [
+                'internal_name'            => 'countries_continents.fly_to_europe',
+                'name'                     => 'Bonjour from Above',
+                'short_description'        => 'Fly to Europe.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $countriesAndContinents,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'countries_continents.fly_to_south_america',
+                'name'                     => 'Southern Cross',
+                'short_description'        => 'Fly to South America.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $countriesAndContinents,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'countries_continents.fly_to_north_america',
+                'name'                     => 'Stars, Stripes & Contrails',
+                'short_description'        => 'Fly to North America.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $countriesAndContinents,
+                'achievement_difficulty_id'=> $easy,
+            ],
+
+            // -----------------------------------------------------------
+            // Aircraft
+            // -----------------------------------------------------------
+            [
+                'internal_name'            => 'aircraft.fly_on_a_plane',
+                'name'                     => 'Up, Up and Away',
+                'short_description'        => 'Fly on an aeroplane.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'aircraft.fly_on_a_helicopter',
+                'name'                     => 'Chop Chop',
+                'short_description'        => 'Fly on a helicopter.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $moderate,
+            ],
+            [
+                'internal_name'            => 'aircraft.fly_on_a_jet',
+                'name'                     => 'Jet Setter',
+                'short_description'        => 'Fly on a jet-powered aircraft.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $easy,
+            ],
+            [
+                'internal_name'            => 'aircraft.fly_on_a_prop',
+                'name'                     => 'Propeller Head',
+                'short_description'        => 'Fly on a propeller driven aircraft.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $moderate,
+            ],
+            [
+                'internal_name'            => 'aircraft.all_boeing_7x7',
+                'name'                     => 'Seven Heaven',
+                'short_description'        => 'Fly every Boeing 7x7 aircraft family.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => true,
+                'difficulty_description'   => 'Requires flying the 707, 717, 727, 737, 747, 757, 767, 777, and 787 — some of which are no longer in commercial service.',
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $impossible,
+            ],
+            [
+                'internal_name'            => 'aircraft.all_airbus_a3xx',
+                'name'                     => 'Airbus Aristocrat',
+                'short_description'        => 'Fly every Airbus A3xx aircraft family.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => true,
+                'difficulty_description'   => 'Covers the A300, A310, A318–A321, A330, A340, A350, and A380 families. You are likely going to have to go to Iran to get this one.',
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $nearImposs,
+            ],
+            [
+                'internal_name'            => 'aircraft.quad_engine',
+                'name'                     => 'Four on the Floor',
+                'short_description'        => 'Fly on a four-engine aircraft.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => 'Four-engine jets are becoming increasingly rare as twin-engine widebodies dominate long-haul routes.',
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $hard,
+            ],
+            [
+                'internal_name'            => 'aircraft.double_decker',
+                'name'                     => 'Upper Deck Club',
+                'short_description'        => 'Fly on a double-decker aircraft.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => 'Primarily the A380 and 747, which operate on a limited and shrinking number of routes.',
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $hard,
+            ],
+            [
+                'internal_name'            => 'aircraft.single_engine',
+                'name'                     => 'Solo Spinner',
+                'short_description'        => 'Fly on a single-engine aircraft.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $moderate,
+            ],
+            [
+                'internal_name'            => 'aircraft.tri_engine',
+                'name'                     => 'Triple Threat',
+                'short_description'        => 'Fly on a tri-engine aircraft.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => 'Most tri-jets are out of service nowadays, and tri-props even rarer',
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $nearImposs,
+            ],
+            [
+                'internal_name'            => 'aircraft.smaller_manufacturer',
+                'name'                     => 'Break the Duopoly',
+                'short_description'        => 'Fly on an aircraft from a manufacturer other than Boeing or Airbus.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => false,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $aircraft,
+                'achievement_difficulty_id'=> $moderate,
+            ],
+
+            // -----------------------------------------------------------
+            // Airlines & Alliances
+            // -----------------------------------------------------------
+            [
+                'internal_name'            => 'airlines_alliances.all_skyteam',
+                'name'                     => 'Team Player',
+                'short_description'        => 'Fly with every airline in the SkyTeam alliance.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => true,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $airlinesAndAlliances,
+                'achievement_difficulty_id'=> $hard,
+            ],
+            [
+                'internal_name'            => 'airlines_alliances.all_oneworld',
+                'name'                     => 'One World Wonder',
+                'short_description'        => 'Fly with every airline in the Oneworld alliance.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => true,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $airlinesAndAlliances,
+                'achievement_difficulty_id'=> $hard,
+            ],
+            [
+                'internal_name'            => 'airlines_alliances.all_star_alliance',
+                'name'                     => 'Star Collector',
+                'short_description'        => 'Fly with every airline in the Star Alliance.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => true,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $airlinesAndAlliances,
+                'achievement_difficulty_id'=> $hard,
+            ],
+            [
+                'internal_name'            => 'airlines_alliances.all_vanilla_alliance',
+                'name'                     => 'Plain Extraordinary',
+                'short_description'        => 'Fly with every airline in the Vanilla Alliance.',
+                'long_description'         => '',
+                'icon'                     => $icon,
+                'progressive'              => true,
+                'difficulty_description'   => null,
+                'achievement_category_id'  => $airlinesAndAlliances,
+                'achievement_difficulty_id'=> $hard,
+            ],
+
+                // ---------------------------------------------------------------
+                // Fun Challenges
+                // ---------------------------------------------------------------
+                [
+                    'internal_name'             => 'fun_challenges.airline_alphabet',
+                    'name'                      => 'Fly the Alphabet',
+                    'short_description'         => 'Fly with an airline whose IATA code starts with every letter of the alphabet.',
+                    'long_description'          => '',
+                    'icon'                      => $icon,
+                    'progressive'               => true,
+                    'difficulty_description'    => 'Some letters have very few airlines with a matching IATA code, requiring creative routing.',
+                    'achievement_category_id'   => $funChallenges,
+                    'achievement_difficulty_id' => $hard,
+                ],
+                [
+                    'internal_name'             => 'fun_challenges.airport_alphabet',
+                    'name'                      => 'Visit the Alphabet',
+                    'short_description'         => 'Visit an airport whose IATA code starts with every letter of the alphabet.',
+                    'long_description'          => '',
+                    'icon'                      => $icon,
+                    'progressive'               => true,
+                    'difficulty_description'    => 'Certain letters — particularly Q, X, and Z — have extremely limited airport coverage, making this a serious challenge.',
+                    'achievement_category_id'   => $funChallenges,
+                    'achievement_difficulty_id' => $nearImposs,
+                ],
+
+                // ---------------------------------------------------------------
+                // Countries & Continents
+                // ---------------------------------------------------------------
+                [
+                    'internal_name'             => 'countries_continents.all_inhabited_continents',
+                    'name'                      => 'Six of One',
+                    'short_description'         => 'Fly to all six inhabited continents.',
+                    'long_description'          => '',
+                    'icon'                      => $icon,
+                    'progressive'               => true,
+                    'difficulty_description'    => null,
+                    'achievement_category_id'   => $countriesAndContinents,
+                    'achievement_difficulty_id' => $hard,
+                ],
+                [
+                    'internal_name'             => 'countries_continents.all_continents',
+                    'name'                      => 'Seven Wonders of the Skies',
+                    'short_description'         => 'Fly to all seven continents, including Antarctica.',
+                    'long_description'          => '',
+                    'icon'                      => $icon,
+                    'progressive'               => true,
+                    'difficulty_description'    => 'Antarctica has no commercial scheduled service — expect a specialist charter or expedition flight.',
+                    'achievement_category_id'   => $countriesAndContinents,
+                    'achievement_difficulty_id' => $nearImposs,
+
+                ],
+                [
+                    'internal_name'             => 'countries_continents.all_continent_pairs_one_way',
+                    'name'                      => 'Grand Junction',
+                    'short_description'         => 'Fly between every possible pair of continents at least one way.',
+                    'long_description'          => '',
+                    'icon'                      => $icon,
+                    'progressive'               => true,
+                    'difficulty_description'    => 'There are 15 unique continent pairs (excluding Antarctica)',
+                    'achievement_category_id'   => $countriesAndContinents,
+                    'achievement_difficulty_id' => $hard,
+                ],
+                [
+                    'internal_name'             => 'countries_continents.all_continent_pairs_both_ways',
+                    'name'                      => 'There and Back Again',
+                    'short_description'         => 'Fly between every possible pair of continents in both directions.',
+                    'long_description'          => '',
+                    'icon'                      => $icon,
+                    'progressive'               => true,
+                    'difficulty_description'    => "30 different intercontinental flights required, good luck.",
+                    'achievement_category_id'   => $countriesAndContinents,
+                    'achievement_difficulty_id' => $nearImposs,
+                ],
+
+
+        ];
+
+        DB::table('achievements')->insert($achievements);
+    }
+
+    public function down(): void
+    {
+        // Reverse user_achievements
+        Schema::table('user_achievements', function (Blueprint $table) {
+            $table->dropColumn('progress');
+        });
+
+        // Reverse achievements
+        Schema::table('achievements', function (Blueprint $table) {
+            $table->text('description')->after('internal_name');
+            $table->dropForeign(['achievement_difficulty_id']);
+            $table->dropForeign(['achievement_category_id']);
+            $table->dropColumn([
+                'short_description',
+                'long_description',
+                'progressive',
+                'difficulty_description',
+                'achievement_category_id',
+                'achievement_difficulty_id',
+            ]);
+        });
+
+        Schema::dropIfExists('achievement_categories');
+        Schema::dropIfExists('achievement_difficulties');
+        Schema::dropIfExists('notifications');
+    }
+};