A wonderful game! Flight dynamics is based on smooth movements, probably through linear and angular accelerations or forces and torques. It's great that you chose this way of building a controllability model. This gives you the opportunity to increase the realism of the flight dynamics to the level of a good simulator.
It is unusual that such an interesting 3D project is made with Godot.
I will try to come back in the near future and give a more complete analysis of the aerodynamics in your game.