with its wings extended in a gull wing profile]] wing planform shapes: a swept wing KC-10 Extender (top) refuels a trapezoid-wing F-22 Raptor]]A wing is a surface used to produce lift for flight through the air or another gaseous or fluid medium. The wing shape is usually an airfoil. The word originally referred only to the foremost limbs of birds, but has been extended to include the wings of insects (see insect wing), bats, pterosaurs, and aircraft.A wing's aerodynamic quality is expressed as