phpvms/app/Database/factories/AircraftFactory.php

<?php

use Faker\Generator as Faker;

$factory->define(App\Models\Aircraft::class, function (Faker $faker) {
    return [
        'id' => null,
        'subfleet_id' => function() {
            return factory(App\Models\Subfleet::class)->create()->id;
        },
        'airport_id' => function () {
            return factory(App\Models\Airport::class)->create()->id;
        },
        'icao' => $faker->unique()->text(5),
        'name' => $faker->unique()->text(50),
        'registration' => $faker->unique()->text(10),
        'active' => true,
        'created_at' => $faker->dateTimeBetween('-1 week', 'now'),
        'updated_at' => function (array $pirep) {
            return $pirep['created_at'];
        },
    ];
});