The angle of incidence is defined as the angle between the:

The angle of incidence is defined as the angle between the chord line of the wing and a line that is parallel to the longitudinal axis of the aircraft. This measurement is important because it determines the initial upward or downward positioning of the wing relative to the aircraft's body when the aircraft is at rest.

The chord line refers to an imaginary straight line that runs from the leading edge to the trailing edge of the wing, and the longitudinal axis runs through the center of the aircraft from the nose to the tail. This angle affects the aircraft's aerodynamics and can influence lift characteristics during flight. By establishing this angle during the design and assembly of the aircraft, engineers ensure that the aircraft performs optimally during various phases of flight, including takeoff, cruise, and landing.

Understanding the angle of incidence is crucial for pilots because it impacts the overall lift-to-drag ratio, stall characteristics, and the aircraft's overall stability and control. This foundational knowledge aids in making informed decisions during flight operations.