Definition
An aircraft whose wing shape or position can be changed in flight to suit different flight conditions, most commonly by sweeping the wings forward for low-speed flight (takeoff, landing, loiter) and sweeping them rearward for high-speed flight. The pivoting wings allow a single airframe to perform efficiently across a wide range of speeds.
Plain English
An aircraft whose wings can move in flight — typically swinging out for slow flight and swinging back for fast flight — so the same airplane handles well at very different speeds.
Context Anchor
Seen in discussions of aircraft design, high-speed aircraft, and aircraft that need both low-speed handling and high-speed performance.
Derivation
From Latin variabilis (changeable) and Greek geometria (measurement of shape). 'Variable geometry' literally means 'changeable shape' — describing an airframe whose physical form changes during flight.
Why Pilots Care
A straight, extended wing produces good lift at low speeds but creates too much drag at high speeds. A swept wing handles high speeds well but performs poorly at low speeds. Variable geometry lets one aircraft do both, instead of compromising at every speed.
Analogy
It is like adjusting a seat or mirror in a car for the situation, except the aircraft is adjusting part of its own shape to suit the way it is flying.
Intuition Check
Do not read “variable-geometry” as meaning the whole aircraft changes size or becomes a different airplane. It means a designed part of the aircraft’s shape can move or change position, usually the wings.
Example Sentence 1
The F-14's variable-geometry wings sweep forward for carrier landings and sweep back for supersonic flight.
Example Sentence 2
During approach the variable-geometry aircraft extended its wings forward for better low-speed handling and lift.