Which control surface is located furthest from the fuselage and controls the rolling motion of an aircraft?

The aileron is the control surface that is located furthest from the fuselage on the wings of an aircraft. Its primary function is to control the rolling motion, which is the tilting of the aircraft's wings about its longitudinal axis. When a pilot moves the yoke or stick laterally, the ailerons on one wing will deflect upwards while the ailerons on the opposite wing will deflect downwards. This differential movement creates a difference in lift between the two wings, causing the aircraft to roll toward the wing with the deflected aileron.

Other control surfaces, such as the elevator, flaps, and rudder, serve different primary functions. The elevator, located on the horizontal stabilizer, controls pitch (nose up or down motion), while the flaps, also on the wings, mainly modify lift during takeoff and landing. The rudder, located on the vertical stabilizer, controls yaw (left or right motion). Since each of these surfaces plays distinct roles in managing different aspects of aircraft movement, their placement and purpose differ. Thus, the aileron's specific role in controlling roll makes it the correct answer in this context.