Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Denmark - Zeppelin Flight - 1936 (May 6-9), Airship ''Hindenburg'' 1st NAF cover, franked by three values, including two air post stamps, tied by Copenhagen ''4.5.36'' ds, Frankfurt connection and letter ''d'' red confirmation cachet, arrived to NYC on May 9, VF, Sieger #406C, Scott #C9-1