Lockheed Electra Airliner, 1935.

UNITED KINGDOM - JANUARY 15: Lockheed 10A Electra, serial no 1037, made in 1935, on display in the �Making the Modern World� gallery, Science Museum, London, 2007. The Electra first flew in February 1934, and with its low-wing, all-metal monoplane contruction, supercharged air-cooled wing-mounted engines, retractable undercarriage, variable-pitch propellers and wing flaps, helped revolutionise air transport. In 1938 Prime Minister Neville Chamberlain flew three times to Germany in a Lockheed 10 to try and prevent war. The Electras operated routes from New York to New Orleans and from Chicago to Indianopolis, with several intermediate stops. After about two years the 10-seat capacity of the Electra was inadequate to meet passenger demand and was replaced. (Photo by SSPL/Getty Images)