Nice, I think the core of your game is shaping up well. The movement mechanics are fun. "Dropping" and whipping around to kill the guys chasing you feels really good. I like to charge into them while blasting. Few things I noticed that might improve it
- I think the camera movement could be improved. In my experience, a lerping camera feels best. Make the camera move towards its target at a rate of X% of the distance each frame (adjusted by the framerate of course). You can tweak the % to suit the speed and all that, but it keeps things moving in a smooth way.
- The acceleration feels a bit too high, making the movement slightly too exact. If the acceleration was a bit weaker, I think it would help sell the fact that this is a giant heavy jet flying around, and the engines firing take a moment to give you forward movement. This would add a lot of play to the movement I think.
Anyway I think you're on track. Keep going, this is a solid start. Also, don't underestimate how much getting a consistent look among things helps with a games feel. The look of the plane is great, might want to get some sort of vector drawing program and turn all the sprites into similar looking "vector art".