1916 (23 Oct) card from Koslin (today Koszalin) with violet "Militar-Fliegerschule/Koslin" cachet, also (15 Apr) postal card from Thorn (Torun), with departure cds and violet "1 Komp. Flieger beobachter schule Thorn." (Flight observer school in Torun), text referring to flight group from Torun and other military matters, fine-v.f. (Image)

Est.$200

1925 (14 Feb) first flight Warszawa to Bucharest, regular 3gr, 15gr and 50gr franking, appropriate cachet and markings, v.f. (Image)

Est.$150

1928 (30 Sep) four covers flown from Siniawka, Kuznica, Maloryta and Wasilkow to Warszawa, each franked with "Poczta Balonowa 1zl L.O.P.P." adhesive, used in combination with regular 5gr franking, tied by "Raid Balonow Kulistych" cds, with corresponding "Balon Lwow", "Balon Warszawa", "Balon Krakow" and "Balon Poznan" handstamps alongside, v.f., scarce (Image)

Est.$500

1936-39 selection of 11 different covers and cards on pages, with Balloon Post (3) with appropriate L.O.P.P. labels used in combination with regular stamps, also first flights and various legs Warszawa-Wilno-Helsinki, Warszawa-Budapest, Warszawa-London, Rome, Belgrade, etc., mostly v.f. (Image)

Est.$250

1939 (9 Sep) two cards "Gordon Bennett", with Belgian stamps and Poczta Balonowa labels, each with appropriate markings, including "Anulowany z Powodu Wojny" (annulled due to war), v.f. (Image)

Est.$150