What does the term "control surfaces" refer to?

The term "control surfaces" specifically refers to the movable parts of an aircraft that are used to control its orientation and stability during flight. These surfaces include ailerons, elevators, and rudders, which adjust the aircraft's attitude and direction by changing the airflow around the wings and tail. By manipulating these control surfaces, pilots can execute maneuvers such as banking, climbing, descending, and turning, which are essential for effective aircraft operation.

The fixed components of the aircraft, while crucial for its overall structure and aerodynamics, do not contribute to changing its orientation, which is the primary role of control surfaces. Components that affect only speed do not encompass the full function of control surfaces, as these typically address motion in multiple axes rather than just increasing or decreasing velocity. Additionally, non-aerodynamic features do not play a role in the aircraft's ability to maneuver through the air, thus are not classified as control surfaces.