Which control surface mostly influences the roll of the aircraft?

The ailerons are the primary control surfaces that influence the roll of an aircraft. They are located on the trailing edge of each wing and operate in opposition to each other. When the pilot wants to roll the aircraft to the right, the right aileron deflects upward while the left aileron deflects downward. This creates a difference in lift between the two wings, causing the right wing to drop and the left wing to rise, resulting in a roll to the right.

Ailerons are specifically designed for this purpose, allowing pilots to bank the aircraft during turns or to maintain level flight by compensating for any roll due to turbulence or other factors. In contrast, the elevator mainly controls pitch, the rudder affects yaw, and wing flaps are used to increase lift and drag during specific phases of flight, such as takeoff and landing. Each of these surfaces has distinct roles, but the ailerons are crucial in managing the aircraft's roll tendency.