Aileron

Ailerons are hinged flight control surfaces attached to the trailing edge of each wing, near the wingtips. They work in opposition — when one aileron deflects upward, the other deflects downward — to control the aircraft's roll axis (banking left or right).

When the pilot moves the control yoke or sidestick to the left, the left aileron rises (reducing lift on that wing) and the right aileron lowers (increasing lift), causing the aircraft to roll left. This differential movement is the primary means of initiating and controlling turns.

Modern large aircraft often have both inboard ailerons (used at high speed) and outboard ailerons (used at low speed and locked out at cruise to prevent wing twist). Some aircraft supplement ailerons with spoilerons — spoiler panels that deploy asymmetrically to assist roll control.