UNTIL THE 1930s, most passenger aircraft were biplanes, with two pairs of wings and a wooden or
metal framework covered with fabric or, sometimes, plywood. Such aircraft were restricted to low speeds and low altitudes because of the drag on their wings. Many had an open cockpit, situated behind or in front of an enclosed—but unpressurized—cabin that carried a maximum of 10 people. The passengers usually sat in wicker chairs that were not bolted to the floor, and the journey could be bumpy when flying through turbulence. Warm clothing, and ear plugs to reduce the effects of prolonged noise, were often required. During the 1930s, powerful, streamlined, all-metal monoplanes, such as the Lockheed Electra shown here, became widespread. By 1939, the advent of pressurized cabins allowed fast flights at high altitudes, where there is less turbulence. Flying boats were still necessary on many routes until 1945 because of inadequate runways and the frequency of emergency sea landings. World War II, however, resulted in enough good runways being built for landplanes to become standard on all major airline routes.
