Trying to define a many-to-many relation with a pivot model in Laravel 8 - laravel

Question

Trying this for hours now and I don't see the error. I have a model 'User' and a model 'Round'. I want to define a n:m-relation with a model 'Flight' as pivot model.
User.php
<?php
namespace App\Models;
use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;
use Spatie\MediaLibrary\HasMedia;
use Spatie\MediaLibrary\InteractsWithMedia;
use Spatie\Image\Manipulations;
use Spatie\MediaLibrary\MediaCollections\Models\Media;
class User extends Authenticatable implements MustVerifyEmail, HasMedia
{
use Notifiable;
use InteractsWithMedia;
/*
.....
*/
public function rounds() {
return $this->belongsToMany(Round::class)->using(Flight::class);
}
}
Round.php
<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Model;
class Round extends Model
{
/*
.....
*/
public function users() {
return $this->belongsToMany(User::class)->using(Flight::class);
}
}
Flight.php
<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Relations\Pivot;
class Flight extends Pivot
{
public $incrementing = true;
/*
.....
*/
}
I made several migrations and seeder.
RelationSeeder.php
<?php
namespace Database\Seeders;
use Illuminate\Database\Seeder;
use App\Models\Round;
class RelationSeeder extends Seeder
{
/**
* Run the database seeds.
*
* #return void
*/
public function run()
{
$round = Round::find(1);
$round->users()->sync([1]);
}
}
When running artisan migrate:refresh --seed all tables are created as expected, but the following error occurs on seeding
SQLSTATE[42S02]: Base table or view not found: 1146 Table 'tour.round_user' doesn't exist (SQL: select * from round_user where round_id = 1)
Obviously Laravel is looking for a standard named pivot-table and not for the desired flights-table.
I am using Laravel 8 in a Docker-Container with Sail.
Where is my mistake?

Answer 1

I found my mistake. With using the pivot model, the name conventions for the intermediate table stay valid. It works with
public function rounds() {
return $this->belongsToMany(Round::class, 'flights')->using(Flight::class);
}
and same thing in the inverse definition
public function users() {
return $this->belongsToMany(User::class, 'flights')->using(Flight::class);
}
Thank you everybody who is helping here - I solved 1000s of problems reading your posts!