Russia has a limited supply of working jets, and limited supply of good pilots. Which they need elsewhere across their very large country and in other places (Syria).
In addition, Russia pulled back its air operations not because of Ukraine jets, but because of ground based air defense (missile that shoot down planes). Trading pilot/plane for pilot/plane is good for Russia, but trading a pilot/plane for a missile is a bad trade for anyone.
Controls felt a little janky to me, but I loved the game. I would recommend it to anyone wanting a shorter Metroidvania experience, especially if the art style is appealing to you.