Great game ! I had a fun time zooming through every screens, and the game really makes you want to speedrun it.
Some minor criticisms, even if I agree with what most people already said here, but the vertical flight feels indeed a bit clunky. However, if you want to make the flight realistic, I think it's not that much of a problem, jsut maybe go for less vertical levels when designing the screens. Also, I can't help but to see some huge similarities with some Celeste sprites everywhere. I suppose that it was a good starting point for you to design some screens, but I hope that in the future the artistic direction will be stronger.
I'll look forward for some content and improvments, keep up the good work, you are going the right way !