the S-40, the first of the “Clipper” flying boats (so named by Trippe himself). The first of the S-40s, the Caribbean Clipper, began service in 1931 (it was christened by Mrs. Herbert Hoover in a ceremony on the Potomac River) and was followed by the American Clipper. Beginning in November 1931, Trippe began to establish extensive international mail and passenger services to the Caribbean and then to South America using three S-40 flying boats. The longer-range S-42 began passenger service in South America in August 1934.
In 1934 Sikorsky stunned the aviation world by building an even better and more luxurious clipper: the S- 42. This time, the nacelles (the engine and propeller housings) were built into the wing so that the wing could be mounted just over the fuselage. The craft still relied on pontoons extending down from each wing for balance in the water, but the entire aircraft was sleeker, which accounted for its cruising speed’s going up to 140 miles per hour (225kph)