Abstract: An aircraft comprising a generally annular wing structure surrounding a circular central structure to form an annular air duct, a pair of fuselages extending longitudinally at opposite sides of the aircraft, and rotor blades extending radially across the air duct from the central structure and rotatable relative to the central structure around the duct for inducing airflow through the duct to effect a lift on the aircraft. The annular wing structure consists of forward and rear wings forming air foils, the forward wing having a generally semicircular trailing edge and the rear wing having a generally semicircular leading edge.