The Boeing Model 307 Stratoliner was the first fully pressurized airliner to enter service anywhere in the world. Capable of flying 20,000 feet higher than the 5,000 to 10,000-foot altitude unpressurized airplanes at that time, it was said that it could “fly above the weather�. The Model 307 had a capacity for five crew members and 33 passengers, and had a nearly 12-foot wide cabin for overnight berths. It was the first plane to include a flight engineer as a crew member.

Only ten Stratoliners were produced. Three were built for Pan Am, five served with TWA, and a ninth was supplied to multi-millionaire Howard Hughes. The prototype crashed during a test flight. By 1940, the Model 307 was flying routes between Los Angeles and New York, as well as to locations in Latin America. Howard Hughes purchased a model for his personal use, and had it transformed into a luxurious “flying penthouse�. This same plane was later sold to oil tycoon Glenn McCarthy in 1949.

The only surviving Stratoliner, operated by Pan Am, is preserved in flying condition at the Smithsonian Museum's Steven F. Udvar-Hazy Center. On March 29, 2002, this particular aircraft was subject to a dramatic crash in which it ditched into Elliott Bay in Seattle, Washington, on what was to be its last flight before heading to the Smithsonian. Despite the incident, it has again been restored and is now on display.