A system and method for moving an aerial vehicle along a flight path includes rotatable hubs mounted on opposite sides of the vehicle. Elongated airfoils are mounted on the hubs parallel to a common hub axis for rotation about the hub axis on a blade path. Each airfoil defines a chord line and the system includes a gear assembly changeable, during hub rotation, between a first modality wherein airfoil chord lines remain tangential to the blade path (curtate flight), and a second modality wherein airfoil chord lines remain parallel to the flight path of the vehicle (prolate flight). Also, rotation of the hub can be stopped and the airfoils used for fixed wing flight.