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.