It seems that pressing the escape key whilst in a jet (either on the ground or in the air) can cause unexpected and unwanted control input. This was discovered during a testing session earlier today and has been confirmed by four separate people on a locally hosted server. I cannot reproduce it in single player as the game pauses, unlike in multiplayer.
When escape is pressed, one of several things can happen, at present, we have noticed the following; Thrust increases, thrust decreases, speed/air break deploys, flaps rise or lower.
It seems to be centred around the aircraft's control surfaces and can make operating them on the ground or the air a pain as they do things that are unexpected. This seems to become prevalent when using custom GUI as well, such as INS/GPS bombing interfaces. Clicking on buttons on the interface had similar effects, though I have no idea how to test this in an unmodded environment.