Definition
An aileron is a hinged control surface on the trailing edge of an airplane wing. It's used to control the aircraft's roll, allowing it to turn. Think of it like the rudder of a boat, but for controlling flight direction in the air. Unlike flaps, which affect lift and drag, ailerons primarily control roll. They work in pairs, with one moving up and the other down, creating an imbalance of lift that causes the plane to roll.