Plain English Meaning
The rules of how air behaves around an aircraft and how that air makes the aircraft fly, turn, climb, and descend.
Full Definition
The body of physical laws and concepts that explain how air interacts with a moving aircraft to produce lift, drag, thrust, and weight, and how those forces govern flight performance, stability, and control.
Context Anchor
You will meet this phrase in ground lessons, flight lessons, and instructor explanations about how the airplane responds to control inputs and changes in speed.
Derivation
From Greek 'aer' (air) and 'dynamis' ( or ), combined with 'principles' (foundational rules). Together: the foundational rules governing the forces of air in motion.