Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Russia And Soviet Union - First and Pioneer Flights - 1926 (July 2-3), Pioneer Flight registered cover from Moscow to Kharkov (4th line opening), franked by three surcharged air post values, all appropriate markings and Kharkov ''3.7.26'' arrival ds on reverse, mostly VF, Est. $200-$250 , Scott #C6-7, C9