The S-40 came with full landing gear, but it could and was often removed to save weight. Ring cowlings were quickly removed from the R-1860 Hornet B engines. These were replaced with supercharged R-1690 Hornet T2D1s in 1935 to produce the S-40A. Photo by: Jesse S Wooley / University of Miami

The first of three S-40 flying boats for PAA, first flown on 6 August 1931. Large airliners for their day, they carried up to 38 passengers. First Lady Lou Hoover christened N80V the first Pan Am Clipper, American Clipper, on 12 October 1931. Charles Lindbergh piloted it on its first scheduled flight from Miami one week later, although he was critical of the draggy design. Photo from: Nationaal Archief (Netherlands)