Ground Effect

Ground Effect is the increased lift and reduced induced drag experienced by an aircraft when flying at a height less than approximately one wingspan above the surface. The ground interrupts the wing tip vortices, reducing downwash and induced drag.

Ground effect is significant during takeoff and landing: it can cause the aircraft to become airborne before reaching the proper climb speed, or to "float" during landing, requiring more runway for stopping. Pilots must account for ground effect in their technique.