Soviet Union – First Flight 1928 (September 17-18), Dobroliot Flight pre-printed (Soviet Philatelic Association) registered cover from Moscow to Irkutsk, franked by three adhesives, violet Dobroliot confirmation cachet and Irkutsk arrival ds on reverse, F/VF and rare, reportedly only 42 flown, Est. We guarantee authenticity with no time limit of all lots posted for sale. […]