Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Canada - Zeppelin Flight - 1936 (May 11-14), Airship Hindenburg 1st NA Return Flight from NYC to Germany, mixed franking cover from Montreal to Frankfurt, franked by Daedalus 6c red brown and upon arrival to New York uprated by 4 US adhesives, violet confirmation cachet and arrival ds on reverse, mostly VF and scarce, Sieger #409 (G) var, Est. $500-$600, Scott #C5