The first of the "Clippers" was the Sikorsky S-40 flying boat, which Pan Am flew on its South American routes 

On 22 Nov. 1935, the bigger Martin M-130 China Clipper went into mail service across the Pacific.  Passenger service followed the following year.   The trip left San Francisco, stopped 6 times and arrived in Hong Kong, taking several days.  At intermediate stops along the way (which were very small islands), Pan Am built hotels for the passengers, but the Martins also had sleeping cabins and a dining room.  Even though the plane was about 1/3 the length of a 747, it typically carried less than a dozen passengers on this punishing route.

In 1939, Pan Am turned to the Atlantic.  The Boeing 314 flying boat was bigger than the Martin and could carry 74 people at full capacity.  On 28 June of that year the Dixie Clipper carried 22 people from Port Washington, NY to Marseilles, France.  The fare was $675, which is about $4,000 today.

During World War 2 the people and the clippers of Pan Am served honourably, and many were lost.