Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Danzig - Zeppelin Flight - 1928 (October 11-15), America Flight cover franked by Large Airplane 2½g violet brown in horizontal pair, tied by oval ''4.10.28'' date stamp, blue oval confirmation marking on front and NYC ''16.OCT.1928'' drop on reverse, VF and scarce, Sieger #21, C.v. €650++, Est. $300-$400, Scott #C30 x2