some refactoring for tests and adding some tables

database/factories/AircraftClassFactory.php

@@ -0,0 +1,10 @@
+<?php
+
+$factory->define(App\Models\AircraftClass::class, function (Faker\Generator $faker) {
+    return [
+        'id' => 1,
+        'code' => 'H',
+        'name' => 'Heavy',
+        'notes' => 'Heavy aircraft',
+    ];
+});