This was envelope sent from Deutsche to Rio de Janeriro, Brasil on April 1, 1936 via Zeppelin by Hindenburg airship which was a biggest airship at diameter 136 feet and bigger than Graf Zeppelin at 100 feet of diameter. Hindenburg still holds the record as the largest aircraft ever to fly, A size comparison of the Hindenburg with mutiple 3 length of a 747. The Titanic is only 78 feet longer than the Hindenburg at 882 feet long.