An improved ground-surface-effect winged craft has a main body in the shape of an airfoil, side plates extending nearly vertically at the opposite lateral sides of the main body for intercepting air flowing outwards from the underside of the main body, side plate floats provided at the side plates, a float provided at a central lower portion of the main body, an operator's seat provided on the float, vertical and horizontal tails provided at a rear portion of the main body, and a propelling device for lifting and propelling the airframe of the craft by making use of both a power augment ramwing effect with the horizontal tail and a ground-surface-effect generated between the main body and a flat surface such as a water surface or a ground surface.