Photograph of first three Boeing B-314s built for Pan American Airways
image from page 1 of Pan American Air Ways, Vol. 10, No. 1, March 1939. Caption reads: "The first three of the great Boeing-built Clippers pose for their pictures on Seattle's Lake Washington, prior to delivery to Pan American Airways for transocean service. As this is written, one of them has just returned from Hong Kong, another is in San Francisco ready to start for the Orient, and the third, the new Flagship of the Pan American Fleet, christened "Yankee Clipper" by Mrs. Roosevelt, is proving itself on the Atlantic to whose base the first of the B-314 series has been delivered."