The Boeing 377 Stratocruiser was a long-range postwar airliner with four piston-driven engines. It was a civilian equivalent to the C-97 Stratofreighter, and was developed largely in parallel with its military sibling.
Despite a service record remembered for one or two early disasters arising from a propeller design fitted to the Stratocruiser in its earlier years, Boeing's remarkable airliner was one of the most capable of post-war propeller-driven transports, and certainly among the most luxurious. Only 55 were built as airliners, joined eventually by the reconditioned prototype to make a total of 56. Another 60 of this general design, with significant engineering differences, were built as C-97 military transports, but the majority were built as KC-97 tankers, with many more military successors to follow. The jet-powered Boeing 707 would regain Boeing's dominance in the civil airliner market, while the KC-135 would continue to serve as a jet tanker into the twenty-first century. The Lockheed C-130 of the mid-1950s was somewhat similar in size and speed, but it had turboprop power and was designed from the start as a combat airlifter, with a tail ramp and ability to operate from rough fields, so is not strictly comparable.