What is the position of the airplane relative to the horizon called?

The position of the airplane relative to the horizon is referred to as the attitude. This term describes the aircraft's orientation in three-dimensional space, specifically its pitching (nose up or down), rolling (tilting side to side), and yawing (turning left or right) movements in relation to the horizon.

Understanding attitude is crucial for pilots as it affects various aspects of flight, including stability and control. By maintaining the correct attitude, a pilot ensures that the aircraft is flying in the desired direction and at the appropriate angle, which is essential for safe flying, especially during maneuvers and in varying weather conditions.

In this context, the other terms have specific meanings that do not relate to the orientation of the aircraft relative to the horizon. Heading refers to the direction in which the aircraft's nose is pointing, while altitude indicates the height of the aircraft above sea level. Trajectory describes the path of the aircraft as it moves through the air, but does not specifically address the aircraft's orientation concerning the horizon. Hence, attitude is the correct term that encompasses these orientation aspects.