It was intentionally put in by HTC. It is there to stop the "stick stirrers". A stick stirrer is someone who when in trouble, twists, yanks, and swings his stick through all kinds of gyrations to make himself a hard target to hit. From the other guys point of view it looks like your plane is flip flopping all over the sky. The idea is if your doing maneuvers that would be impossible to do in a plane due to G forces, or just not possible mechanically, you can't do it in the game.