how to add key when we get list of data from database in laravel using model code example

Example 1: laravel fillable

/**
     * The attributes that are mass assignable.
     */
    protected $fillable = [
      					   'title',
                           'slug',
                           'body',
                           'image',
                           'published',
                           'comments_open'
                          ];

Example 2: laravel find query

return Destination::orderByDesc(
    Flight::select('arrived_at')
        ->whereColumn('destination_id', 'destinations.id')
        ->orderBy('arrived_at', 'desc')
        ->limit(1)
)->get();