First clipper Pan-Am airmail flight Prague to Vienna, envelope 1946 stock photo
{"Image ImageDescription": "London, England - December 5, 2011: An old grey envelope with a message stating that it was on the first Pan Am Clipper airmail flight from Prague to Vienna in 1946. Pan American World Airways (Pan Am) was the largest airline in the USA until it collapsed in 1991.", "Image Copyright": "Linda Steward"}