A propliner is a large, propeller-driven airliner. Typically, the term is used for piston engine airliners that flew before the large scale advent of airliners of the jet age. With the notable exception of the de Havilland Albatross and Fokker F-10 of the late 1920s to 1930s, which were largely fabricated of wood, propliners generally featured all-metal wings and structural members, totally or partially retractable landing gear, and two, three, or four engines. A few might deviate from these characteristics with fixed landing gear, such as the Albatross, Fokker 110, and Lockheed Vega.
With the earlier introduction of the Boeing 307 Stratoliner and the experimental Douglas DC-4E, a second generation of propliners emerged. These technologically more modern aircraft featured cabin pressurization systems allowing greater comfort by allowing aircraft to fly higher and above much of the lower altitude weather, although it was not until the Lockheed Constellation, followed by the Douglas DC-6 and Douglas DC-7, that this design advance became common.
