The zero key will only toggle the visibility of the Flight Modes gadget. It will not modify the flight performance of the selected model.
It is possible to edit the models and remove that functionality. Once you learn how it is not difficult, but it does require some expertise in using the built-in aircraft editor. I'm pretty sure I've seen some instructions from other users on this very topic. I suggest searching for that (I'd try "safe removal" or similar keywords).