1930 (September 10-11), Moscow Return Flight stationery card and cover, franked by Zeppelin stamps of 40k and 80k respectively along with other stamps, tied by special Zeppelin ''10.IX.30'' ds, two-line violet confirmation marking, each one with Friedrichshafen ''11.9.30'' receiver, mostly VF, Sieger #85Aa, Bb, Est. $100-$150 (Image)

1930 (September 10-11), Moscow Return Flight postcard to Germany, franked by four adhesives, tied by Moscow special ''10-IX-30'' ds, two-line violet Flight cachet, Friedrichshafen ''11.9.30'' arrival marking, VF and scarce non-Zeppelin franking postcard, Sieger #85D, Est. $150-$200 (Image)

1931 (July 25-27), North Pole Zeppelin Flight registered cover from Leningrad to Ice-Breaker ''Malygin'', franked by perforated complete set of four, tied by Leningrad ''25.VII.31'' special ds, German confirmation cachet, arrival ''27.VII.31'' and all appropriate markings, mostly VF, Sieger #120Ca, €1,300, Est. $500-$600 (Image)

1932 (September 12-16), 6th SAF postcard from Moscow to Pernambuco, franked by three airship stamps, Berlin connection, green confirmation cachet, Pernambuco ''16.X.32'' arrival ds is alongside, VF, Sieger #177, Est. $450-$500 (Image)

1933 (August 5-8), 4th SAF registered cover from Leningrad to Brazil, franked by four stamps, including three Zeppelin adhesives, delivered by flight Leningrad - Berlin with connection ''29.7.33'' ds, two confirmation markings and Pernambuco ''8.VIII.33'' arrival hs, slight traces of mounts on reverse, still VF and scarce, Est. $450-$500 (Image)