Yeah, no-fly zone is basically WWIII. Doesn't seem like a good idea to me.

Depending on how you define it, air superiority can mean you have some advantage in the air (i.e., more / better fighter planes than the enemy) or that you basically own it (enemy planes won't even try to enter). Not clear what the situation in Ukraine is, but I'd expect the Russians to have some level of superiority given they have a lot more planes than Ukraine does.