I love the aesthetics and the idea for the barrel roll unblocking the gun :D
The animations for fire and shooting are nice, the UI is great (presumably :D). WIth some polished music (that maybe changes based on how you're doing?) and a way to prolong the game (healing, shields, multiple lives?), it could be a great game to get into easy and play for a long time.
Maybe you could different kinds of planes, both for the player and the enemies?
Ooh, or aircraft carriers in the sea that you can land on or just pass through a power up above them so that you heal?
Also, maybe this is visible in the UI but some altitude feedback would be good.