This game reminds me of a game called Psyvariar. The mechanism is quite the same. However, your game has clearer graphics and better UI. The shop system is quite amazing and also I think it is the best part in this game. When players click the upgrade, it has smooth feedback and the effect in the game is quite clear. Added with the saving and level choosing, I think the game is quite complete and well designed.
I think what you can improve in the future is, if possible, there can be more planes to choose and even abilities for different planes. But overall, it is a very well done game.