Definition
Hinged control surfaces located on the trailing edge of each wing, near the wingtip, that move in opposite directions to roll the airplane about its longitudinal axis. When the pilot turns the control wheel or moves the stick left, the left aileron deflects up and the right aileron deflects down, causing the airplane to bank left; right input produces the opposite result.
Plain English
The moving panels on the back edge of each wing that the pilot uses to tilt the airplane left or right. They always work as a pair — one goes up while the other goes down.
Context Anchor
Seen during takeoff roll when the pilot uses the controls to keep the wings level, especially in crosswind conditions.
Derivation
From the French aileron, meaning 'little wing' (a diminutive of aile, 'wing'). The name fits — an aileron is a small, movable section of the larger wing that changes how that wing produces lift.
Why Pilots Care
Ailerons allow precise control of bank angle, which is essential for coordinated turns, maintaining level flight, and countering wind effects during takeoff and landing.
Intuition Check
Ailerons do not steer the airplane on the ground like a car’s front wheels. They control the wings’ tilt, which becomes especially important as airflow over the wings increases.
Example Sentence 1
During the takeoff roll in a left crosswind, the pilot held the control wheel into the wind so the left aileron stayed deflected up.
Example Sentence 2
To initiate a left turn, the pilot raises the left aileron and lowers the right aileron.