I hope the Wiki is still not fully updated, so we just have wrong info there. If that’s not the case then again the devs are doing something that doesn’t make any sense.
According to the linked Wiki article, if you will use a lineup of e.g. one 4.0 BR plane, you will get 4.0 BR matchmaker.
But if you use a lineup of 4.0, 3.7, 3.3 planes, you will get 3.7 BR matchmaker, even if you won’t use 3.7 and 3.3 planes in the battle.
This doesn’t make sense, because to get around this new rule, you will just have to add 2 “fake” planes to your lineup. You don’t have to play them, just add them to the lineup to have easier matchmaker. I don’t see any logic here.
Why not just use the same rules as in other game modes and consider the highest BR vehicle in the lineup as the matchmaker BR? If your highest plane has 4.0 BR, just consider this as 4.0 BR lineup. It just makes the most sense and it won’t allow players to downtier powerful vehicles by creating “fake” lineups.
At the same time, Air Arcade really needs a limit of spawns, because some players can spawn 10 or more times and it’s just ridiculous. Why not limiting number of spawns to e.g. 5? Ground Arcade has spawns limited to 3, Naval Arcade has spawns limited to 5 (3 vessels, 2 planes), Air Arcade has no spawn limit (if you have 10 crew slots, you can spawn 20 times using backups).