In aviation, what determines the forward and backward movement of an aircraft?

The forward and backward movement of an aircraft is primarily determined by throttle. Throttle controls the power output of the engines, which essentially influences the thrust generated by the aircraft. When the throttle is increased, the engines produce more thrust, propelling the aircraft forward. Conversely, reducing the throttle decreases thrust, slowing the aircraft down or allowing it to descend.

While pitch involves the angle of the aircraft's nose relative to the horizon and plays a significant role in climbing or descending, it is the throttle that directly dictates the overall speed and forward momentum. Therefore, understanding how throttle functions is crucial for pilots as it directly affects the aircraft's movement in the forward and backward directions.