Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Soviet Union - 1934, the Stratosphere Disaster, 5k, 10k and 20k, used on individual covers together with other values, first one sent in Moscow, the other one - from Kiev to Moscow, the last one - from Moscow to Leningrad, all appropriate markings, mostly VF, Est. $300-$400, Sc. #C50-52