Lot 30010 – 1928 (May 1) First flight envelope Vienna to Leningrad,

1928 (May 1) First flight envelope Vienna to Leningrad, franked with 8g, 30g and 10g tied by cds « Flugpost Wien Aspern » dated I.V.28, with fine strike below stamps, also the violet « Flugfeld Aspen, P. Wien 1 » rectangular cachet top left corner of envelope, arrival on reverse dated 4th May, extremely rare cover – listed in kohl although unpriced due to its rarity – very few examples known.