A vehicle, including a vehicle frame, a duct carried by the vehicle frame with the longitudinal axis of the duct perpendicular to the longitudinal axis of the vehicle frame, a propeller rotatably mounted within the duct about the longitudinal axis of the duct to force an ambient fluid therethrough from its inlet at the upper end of the duct through its exit at the lower end of the duct, and thereby to produce an upward lift force applied to the vehicle, and a plurality of parallel, spaced vanes pivotally mounted to and across the inlet end of the duct about pivotal axes perpendicular to the longitudinal axis of the duct and substantially parallel to the longitudinal axis of the vehicle frame, the vanes being selectively pivotal about their axes to produce a desired horizontal force component to the lift force applied to the vehicle.