Abstract: Systems for propelling and controlling attitude of aircraft. Systems according to certain embodiments of the invention employ a fan whose rotational axis is preferably generally parallel to the yaw axis of the aircraft and which is preferably generally aligned with the center of gravity of the aircraft at least during the vertical phases of flight. Efflux from the fan can be routed downward through a vertical outlet for providing lift and vertical flight, and aft through a propulsion duct for providing thrust in horizontal flight modes. Vanes in the vertical outlet can be used to direct flow of efflux more in a forward or aft direction for “balancing” of the aircraft about the rotor in vertical flight.