PAA's "Clipper" routes in "The Americas" (1936)
1941 advertising mailer for Pan Am's "Flying Clipper Cruises" to South America
Pan Am inaugurated its South American routes using Sikorsky S-38 and S-40 flying boats. The latter were three large passenger craft put in service by Trippe in 1931 to provide greater carrying capacity than the eight-passenger S-38. Carrying the nicknames American Clipper, Southern Clipper, and Caribbean Clipper, they were the first of the series of 28 Clippers that came to symbolize Pan Am between 1931 and 1946.
In 1937 Pan Am turned to Britain and France to begin seaplane service between the United States and Europe. Pan Am reached an agreement with both countries to offer service from Norfolk, Virginia, to Europe via Bermuda and the Azores using the S-40s. Starting in June 1937, a joint service from the U.S. mainland to Bermuda was inaugurated, with Pan Am using Sikorsky flying boats and Imperial Airways using the C class flying boat RMA Cavalier.
On July 5, 1937 the first commercial survey flights across the North Atlantic were conducted. The Pan Am Clipper III, a Sikorsky S-42, landed at Botwood in the Bay of Exploits in Newfoundland from Port Washington, New York, via Shediac, New Brunswick. The next day Pan Am Clipper III left Botwood for Foynes in Ireland. The same day, a Short Empire C-Class flying boat, the Caledonia, left Foynes for Botwood, and landed July 6, 1937, reaching Montreal on July 8 and New York on July 9. These test flights marked the first steps toward commercial transatlantic flights in heavier-than-air craft.
PAA's China Clipper service cut the time of a transpacific crossing from as much as six weeks by sea to just six days by air.
Trippe then decided to start a service from San Francisco to Honolulu, and from there to Hong Kong and Auckland following existing steamship routes. After negotiating traffic rights in 1934 to land at Pearl Harbor, Midway Island, Wake Island, Guam, and Subic Bay (Manila), Pan Am shipped $500,000 worth of aeronautical equipment westward in March 1935 using the North Haven a 15,000 ton merchant ship it chartered for the purpose of provisioning each island that the clippers would stop at on their 4 to 5-day flight. Pan Am ran its first survey flight to Honolulu in April 1935 with a Sikorsky S-42 flying boat. The airline won the contract for a San Francisco – Canton mail route later that year and operated its first commercial flight carrying mail and express (no passengers) in a Martin M-130 from Alameda to Manila amid massive media fanfare on November 22, 1935. The five-leg, 8,000-mile (12,875 km) flight arrived in Manila on November 29 and returned to San Francisco on December 6, cutting the one way travel time in either direction between the two cities via the fastest scheduled steamship service by over two weeks. (Both the United States and Philippine Islands issued special stamps for the two flights.) The first passenger flight left Alameda on October 21, 1936. The fare from San Francisco to both Manila and Hong Kong in 1937 was $950 one way (about $14,700 in 2010) and $1,710 round trip (about $26,400).
Stamps issued by the United States and Philippine Islands for Air Mail carried on the first flights in each direction of PAA's Transpacific "China Clipper" service between San Francisco, CA, and Manila, PI. (November 22 – December 6, 1935)
On August 6, 1937 Juan Trippe accepted United States aviation's highest annual prize, the Collier Trophy, on behalf of PAA from President Franklin D. Roosevelt for the company's "establishment of the transpacific airline and the successful execution of extended overwater navigation and the regular operations thereof." Later, Pan Am used Boeing 314 flying boats for the Pacific route: in China, passengers could connect to domestic flights on the Pan Am-operated China National Aviation Corporation (CNAC) network, co-owned with the Chinese government. Pan Am flew to Singapore for the first time in 1941, starting a semi-monthly service which reduced San Francisco–Singapore travel times from 25 days to six days. The Boeing 314s were used on transatlantic routes starting in 1939.
Flown cover carried around the world on PAA Boeing 314 Clippers and by Imperial Airways, June 24 – July 28, 1939
Pan Am's flying boat terminal at Dinner Key in Miami, Florida, was a hub of inter-American travel during the 1930s and 1940s.
Six large, long-range Boeing 314 flying boats were delivered to Pan Am in early 1939. The new type enabled commencement of a regular weekly transatlantic passenger and air mail service between the United States and Britain on June 24, 1939. The route was from New York via Shediac, Botwood, and Foynes to Southampton. After the outbreak of World War II, the terminal became Foynes until the service ceased for the winter on October 5; transatlantic service to Lisbon via the Azores continued into 1941. Throughout the war, Pan Am flew over 90 million miles (145 million kilometers) worldwide in support of military operations.
In 1940 Pan Am and TWA began using the Boeing 307 Stratoliner for passenger services. It was the first pressurized airliner to go into commercial service and the first to include a flight engineer as a member of the crew. The Boeing 307's airline service proved short-lived, as all five models built were commandeered for military service at the outbreak of World War II.
The "Clippers" — the name hearkened back to the 19th century clipper ships – were the only American passenger aircraft of the time capable of intercontinental travel. To compete with ocean liners, the airline offered first-class seats on such flights, and the style of flight crews became more formal. Instead of being leather-jacketed, silk-scarved airmail pilots, the crews of the "Clippers" wore naval-style uniforms and adopted a set procession when boarding the aircraft. The China Clipper became well known for its South Seas routings.
In 1942, while waiting at Foynes, County Limerick, Ireland for a Pan Am Clipper flight to New York, passengers were served a drink today known as Irish coffee by Chef Joe Sheridan.
During World War II most of the Clippers were pressed into military service. Pan Am pioneered a new air route across Western and Central Africa to Iran, and in early 1942 the airline became the first to operate a route circumnavigating the globe. Another first occurred in January 1943, when Franklin D. Roosevelt became the first U.S. president to fly abroad, in the Dixie Clipper. During this period Star Trek creator Gene Roddenberry was a Clipper pilot; he was aboard the Clipper Eclipse when it crashed in Syria on June 19, 1947.