Abstract: The invention provides the means for controlling the direction of travel of a surface effect vehicle, that is a vehicle arranged to be supported above a land or water surface, the control means comprising differentially operable aileron like flaps arranged to selectively exert a tilting moment on the craft about its longitudinal axis during motion to assist in the control of the vehicle during a turn. The craft is preferably provided with two fan propulsion units and the aileron like flaps are preferably arranged in the slipstream of those fan units. The aileron like flaps may also be used to control differentially the thrust of such fan units for steering purposes alone or in conjunction with conventional rudders.