Air Mail cover 1918 (8 July) Krakau-Budapest flight envelope (opened out for display) bearing Austria Air 2.5Kr. and 4Kr., together with on reverse 15h. strip of five, all cancelled by "KRAKAU" c.d.s. with similar "FLUGPOST" c.d.s. adjacent, "FLUGPOST/WIEN" c.d.s. (same day) adjacent though showing no arrival marking. Stated to be unique. Photo