Pan Am operated the first scheduled transatlantic passenger service in 1939. The airline used Boeing 314 flying boats for its pioneering route between the United States and Europe.
The inaugural service connected Port Washington, New York, with Lisbon, Portugal, through intermediate stops. Flying boats were chosen because many airports at the time lacked runways suitable for very large, heavily loaded aircraft.
This service was very different from modern airline travel. Flights took many hours, fares were extremely expensive, and aircraft carried fewer passengers than later landplanes. Pan Am had already built a reputation for long-distance flying across the Pacific and Atlantic.
The 1939 service is often confused with later postwar landplane routes. Commercial transatlantic aviation expanded much more rapidly after aircraft such as the Lockheed Constellation and Douglas DC-6 entered service.