12/31/2009. Four S-307 Stratoliners (registered NC19901 to NC19903, NC19910 c/n 1994, 1995, 2003, 2002) were built for Pan American Airways under Type Certificate 719 (they were also known as PAA-307s). After loss of the first aircraft, the remaining three were delivered to the airline with the new dorsal fin and enlarged vertical tail surfaces. Externally, the S-307 could be distinguished from the other models by the absence of external wing flap hinges.
Named Flying Cloud, Cornet and Rainbow, the three remaining PAA-307s were based at Miami, Florida, for use on PAA's Latin American routes.
During WW II they served the military, but with civil registration, and were sold after the war when Model 377 Stratocruisers became available. After serving various foreign owners, in Honduras, Ecuador and elsewhere, the three PAA-307s eventually returned to U.S. registration.
NC19903 is the sole surviving aircraft of ten aircraft produced (four S-307s, five SA-307Bs, one SA-307B-1) and is on display at the Steven F. Udvar-Hazy Center of the Smithsonian Museum.