While this is definitely a contrived cover, the question is did it pay the correct rate ? What was the Around the world rate in 1929 ? This is a cover from the LZ-127 Zeppelin Around the world flight. The Franking adds up to $1.85 if I added correctly, now all I need to do is determine how far this letter flew.... Here is a little tidbit about it.
http://www.wingnet.org/rtw/RTW001J.HTM
