Junkers F.13

The Junkers F.13 is a German aircraft built by Junkers, first flown in 1919 and widely regarded by aviation historians as the world's first all-metal, cantilever-wing aircraft purpose-built for commercial passenger transport, using a corrugated duralumin skin that gave the wing structural strength without external bracing wires. Produced in substantial numbers through the 1920s and into the 1930s and operated by airlines on several continents, it established design principles, an all-metal monoplane airframe carrying its own structural loads through the skin and wing, that influenced the development of later airliners well beyond Junkers' own later designs.