Air Mail cover 1919 (11 Mar.) unstamped envelope (small faults) carried on Baghdad-Cairo survey flight of 31st. Wing, R.A.F., showing "POSTAL SERVICE, M.E.F./AERIAL MAIL, BAGHDAD-CAIRO/BY 31 ST. WING. R.A.F. MESOPOTAMIA" cachet in magenta cancelled by F.P.O. 55 c.d.s. at right, Army Post Office SZ10 c.d.s. on reverse. Photo