Air Mail cover 1924 (1 Aug.) Peking - Tientsin special flight XU5 bearing 3c. and Air 90c. (a few trimmed perfs.) cancelled by c.d.s. (1.8), showing bilingual "To be despatched by/Aerial Service" h.s. adjacent and arrival c.d.s. (2.8) on reverse. Very rare special flight in connection with an Air Exhibition, only five covers recorded by Starr and Mills. Photo