What is an aileron?

An aileron is a crucial control surface located on the wings of an aircraft, specifically designed to help roll the aircraft around its longitudinal axis, which extends from the nose to the tail. When a pilot moves the control yoke or stick to one side, one aileron moves upward while the other moves downward. This movement causes a difference in lift between the two wings, resulting in the aircraft rolling to the side with the descending aileron. This rolling motion is essential for turns and maneuvering in flight.

In contrast, other options do not accurately describe the function of an aileron. The adjustment of aircraft speed is typically managed by throttle controls and not directly related to aileron operation. Control of climbing and descending flight attitudes is primarily handled by the elevator, not the ailerons. Furthermore, airspeed is measured using an instrument known as an airspeed indicator, rather than through aileron function.