Currently the game only supports throttle systems that have only positive values on their axis of motion. Some throttles (like the Thrustmaster FCS) have half negative and half positive values on their axis and this causes some weird interactions with the game.
When flying jets for example only half of the throttle motion is recognised; with the throttle fully backwards if you start pushing on it the engine will turn on but nothing will happen until you reach halfway and hit the positive values and at that point the trust will start to go up rapidly. This makes it particularly hard to fly jets or helicopters for that matter as it's nearly impossible to hover mid air because as soon as you push the throttle a little bit away from centre the collectives will start to go up or down very rapidly.