To stabilize an aircraft body by stream-lining the turbulence of an air flow behind the wheels of an aircraft when ready for landing and lowering the wheels and to reduce the wear of tires when landed by reducing a difference between a landing speed and a wheel peripheral speed.

Each of vanes radially mounted at the rotational center C of a wheel has a pressure difference forming curve 10 to generate a pressure difference at the upper and lower sides of the vane with an air flow A and rotate R the wheel to the moving direction of an aircraft with the couple M caused by the pressure difference. The air flow A from the moving direction F of the aircraft when ready for landing and lowering the wheels is used for power source to rotate R the wheel, so that the turbulence of the air flow A behind the wheel is rectified, the oscillation of the body caused by the turbulence of the air flow A is restricted, a difference between the landing speed of the aircraft and the peripheral sped of the wheel is reduced and the wear of a tire when landed is reduced.