Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Russia And Soviet Union - First and Pioneer Flights - 1931 (June7-9), two Pioneer Flight registered covers (presumably FDC), sent from Moscow to Berlin, franked by Airships 10k-1r, imperforate and perforated complete sets of five, tied by Moscow ''7.6.31'' and ''8.6.31'' date stamps respectively, each one with appropriate arrival ds on reverse, mostly VF, Est. $400-$500, Scott #C15-19, C20-24