Which control surface works primarily along the horizontal axis?

The elevator is a control surface that affects the pitch of the aircraft, which is the movement around the horizontal axis. When the pilot moves the control yoke or stick forward or backward, the elevator changes position, increasing or decreasing the angle of attack at the tail. This action causes the nose of the aircraft to rise or fall, allowing for ascent or descent.

In contrast, ailerons control the roll of the aircraft along the longitudinal axis, while the rudder controls the yaw along the vertical axis. Trim tabs are small adjustable surfaces that help relieve control pressures and achieve a desired flight attitude but do not primarily function along the horizontal axis themselves. Thus, the elevator is specifically designed to manage vertical movement and plays a crucial role in the aircraft's overall control along the horizontal axis.