The Aero A.18 was a biplane fighter aircraft built in Czechoslovakia in the 1920s. It was a development of the Ae 02 and Ae 04 fighters Aero had designed during World War I, but also borrowed from the more recent A.11 reconnaissance-bomber design.
The Aeromarine PG-1 was an American single-seat pursuit (fighter) and ground attack (PG) biplane developed by the Engineering Division of the United States Army and manufactured by the Aeromarine Plane and Motor Co..
