Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Belgium - Zeppelin Flights - 1936 (May 6-9), Airship ''Hindenburg'' 1st NAF cover, franked by three values, including a pair of Airplane 5fr red brown, tied by Brussels ''5.5.36'' ds, letter ''c'' (Frankfurt) red confirmation cachet, backstamped NYC on May 9, VF, Sieger #406C, Scott #C4