Lot 11062 – 1936 Sikorsky “Amphibion” (S-43), world airplane a

1936 Sikorsky “Amphibion” (S-43), world airplane altitude record flight covers for “no load” and 500 kilos (April 14) and for 1000 and 2000 kilos (April 25), diff. cachets, each signed by pilot Boris Sergievsky and his “passenger,” Igor Sikorsky. Rare, the first is a long cover (central fold), very fine (6c Orange airmail on each is oxidized)