An aileron is a movable surface on the wings of an aircraft that helps control its roll. By adjusting the ailerons, pilots can tilt the aircraft to the left or right, allowing for smoother turns and better maneuverability. Ailerons work in pairs, with one moving up while the other moves down, creating a difference in lift between the two wings. Ailerons are typically located at the trailing edge of each wing and are essential for maintaining balance during flight. They are part of the larger control system that includes other surfaces like elevators and rudders, which help manage pitch and yaw, respectively.