Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Soviet Union - Pioneer Flights - 1924 (May 23), Moscow - Koenigsberg - Berlin Flight registered cover forwarded to Paris by connected flight, franked by Lenin Mourning issue perforated complete set in horizontal pairs, tied by Moscow ''23.5.24'' ds, two-line boxed Koenigsberg ''Mit Luftpost...'', Paris ''27.5.24'' arrival marking, slight traces of previous mounts, still F/VF and probably unique franking, Est. $500-$600, Scott #269-72