Flight

Flight is the capacity of self-propulsion through the atmosphere or through space, without contact with the ground. Most birds, many insects, the mammalian bat and flying fox and man-made contraptions (such as aircraft) are capable of true flight; although creatures such as flying fish merely leap. When airplanes fly, air over the top surface moves faster than air under the bottom surface (of the wing). This causes the plane to be sucked upwards.