Pan Am Clipper flying boats were the first true intercontinental passenger airplanes; they crossed the Atlantic and Pacific and circled Latin America in the 1930’s and 1940’s.
The first Pan American flying boat to be called a Clipper was the Sikorsky S-40. The plane was a rugged, capable aircraft that extended Pan Am’s routes around Latin America, but it had been built with old-fashioned tried-and-true technology, rather than modern technical innovations, and it’s high-drag design of exposed struts and wires earned it the nickname of “flying forest.”
The streamlined Sikorsky clipper that followed — the S-42 — was a much more modern airliner, and the S-42 was used both in regular service around Latin America, and also as a survey plane pioneering the trans-pacific routes that would be flown by the next advance in flying boat design, the Martin M-130.
The most famous Martin clipper, and perhaps the most famous flying boat of all time, was Pan American’s China Clipper, which made the first scheduled air mail flight across the Pacific, in November, 1935, flying from San Francisco to Manila with stops at Honolulu, Midway Island, Wake, and Guam. The four engine Martin flying boat had a range of 3,200 miles, but was only able to carry 8-10 passengers on the longest leg of the flight, from California to Hawaii. Passengers slept in individual berths on the overnight flight from San Francisco to Hawaii, and stayed in Pan Am hotels during their overnight stays at Midway, Wake, and Guam.
The B-314 Boeing Clipper, introduced in 1939, was the high point of flying boat design, and Pan Am began the world’s first heavier-than-air passenger service across the Atlantic ocean using the B-314 Boeing clipper. (The German airship Hindenburg had pioneered regularly scheduled passenger flights between Europe and America three years earlier, in 1936.) The Boeing clipper had a range of 3,500 miles and could could carry 74 passengers in luxurious lounges and private sleeping compartments.