The German empire 1935/1939, 13 airmail? letters transported mostly overseas the overseas destinations Brazil ( 3 pieces, everyone to IV.Officer on board of the steamer SS Natal, stamped by it with 3 RM zeppelin once ), Colombia ( 5 pieces, of this one with conducting sticker, " By air mail from New York via P.A.A. " & Scadta and another one by airmail first to steamers Bremen ), Uruguay (2 pieces, of this one by an airmail certified mail) and south Australia, interesting!