Thanks for posting stampdorkman.
Here is an envelope carried on that first US to Frankfurt flight by the Hindenburg.
Philatelic of course.
Rudolf Dinnebier (1880-1946) was a fairly well-known stamp dealer who seems to have made a specialty in aerophilately. Interestingly, a badly burned cover addressed to him was one of the very few (368) pieces of mail salvaged from the 1937 crash, kind of bookending things. That one was sold (not to me) as lot 547 of the Kelleher sale 643 in 2014 at just a tenth of its estimate. https://www.stampcircuit.com/stamp-...hts-zeppelin