Which plane are you using? It sounds like SAFE: Beginner mode or similar is selected, which does indeed restrict the airplane's movements.
I suggest you research SAFE to learn more. Also, pay attention to the Flight Modes gadget in the lower right corner. It shows which modes are available on the currently loaded vehicle (some have no such flight controllers) as well as indicating which mode is currently active. It also gives you more information about what each mode does if you hover the mouse cursor over the question mark, though I'm not sure if that text is fully translated.