Abstract: An aircraft of the hang glider type includes a wing (11) with a keel (12) in its plane of symmetry serving as a fastening point for a trapeze and a harness by which the pilot is suspended below the wing, the trapeze and the harness being disposed in conventional manner for suspending a pilot in the prone position. The invention provides a motor propeller unit (15) which is mounted in such a manner as to be movable at least in the longitudinal direction along the keel axis under pilot control, thereby enabling the pilot to displace both the center of gravity of the motor propeller unit and his own center of gravity between an extreme forward position ahead of the center of lift of the wing and an extreme rearward position behind the center of lift (1).