Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Iran - Pioneer Flight - 1929 (September 1-8), cover from Tehran to Stockholm, franked by three values, delivered by several Pioneer Connecting Flights, including Tehran - Moscow, Moscow - Berlin and Berlin - Stockholm, bearing transits of Moscow (6.9.29), Berlin (6.9.29) and machine Stockholm receiver of September 8, Soviet ''Air Mail'' label and red Berlin connection marking on front, mostly VF and scarce well traveled item, Est. $300-$400, Scott #C26, C28