An aileron is one the three primary flight control surfaces found on aircraft. Ailerons are movable, hinged surfaces that control movement about the longitudinal axis, known as roll. The ailerons are used along with the rudder to make turns.
One aileron is found at the outer trailing edge of each wing. They impart a rolling motion to the aircraft, making banking possible. Lowering the aileron on one wing raises the aileron on the other. The wing with the lowered aileron rises because of its increase lift, and the wing with the raised aileron moves downward because of its decreased lift. Thus, the effect of moving either aileron is aided by the simultaneous and opposite movement of the aileron on the other wing.
Rods or cables connect the ailerons to each other and to the control stick in the cockpit of the plane. Pushing the control stick to the right moves the right aileron up and the left aileron down. This causes the right wing to dip and helps turn the plane to the right. A downward motion of the aileron increases the camber, thus increasing lift and raising the wing. The right aileron moves upward and decreases the camber on the right wing, resulting in reduced lift. Decreased left on the right wing and increased lift on the left wing cause a roll and bank to the right.