What is the key difference between a horizontal stabilizer and a stabilator?

The key difference between a horizontal stabilizer and a stabilator lies in their design and functionality. A horizontal stabilizer is a fixed wing structure that provides stability to the aircraft in pitch but does not have any movable parts itself. Instead, it serves as a surface that aids in stabilizing the airplane's attitude and helps control the aircraft's pitch through a separate elevator that is attached to the rear.

In contrast, a stabilator is a type of horizontal tail surface that combines the functions of both a stabilizer and an elevator into one single movable surface. The entire stabilator can pivot to control the pitch of the aircraft, making it much more responsive to pilot inputs.

Thus, the statement that the stabilator does not move while the stabilizer does accurately outlines the distinction between the two components in terms of their functionality and control mechanics. The stabilizer remains fixed while the stabilator actively changes its angle to affect pitch dynamics of the aircraft.