Avia 156The Avia 156 was a 1930s Czechoslovak six-passenger commercial transport airliner for both mail and passengers, designed by Robert Nebesář and built by Avia. The type performed well but only one was built.DevelopmentThe Avia 156 was a single-engined high-wing cantilever monoplane that first flew in 1934. Powered by a Hispano-Suiza 12Ydrs inline piston engine, it had fixed tailwheel landing gear.