This was a fun little project! Took me a little while to find the sneaky hidden target :D
I found myself wishing that the camera had a little offset from the ship, making it go down slightly when pitching up, etc. for just a little more visual dynamics.
I also would have liked the mouse cursor to use either MOUSE_MODE_CAPTURED or MOUSE_MODE_CONFINED_HIDDEN depending on what kind of input implementation you were using. There were a couple of times when I clicked out of the game window while banking hard.
Hope you had a positive experience using Godot for 3D, and thanks for doing a Linux build!