ST WING R.A.F., MESOPOTAMIA" cachet in violet, F.P.O. 55 c.d.s. and London transit d.s., Army Post Office SZ10, Air Ministry and Paris d.s. on reverse. Photo" /> Air Mail cover 1919 (24 Feb.) Baghdad-Cairo Survey Flight envelope (complete with letter from Capt. Boyd) to London and redirected to Paris, bearing Iraq British Occupation 1a. cancelled by "POSTAL SERVICE, M.E.F./AERIAL MAIL, BAGHDAD-CAIRO/BY, 31<SUP>ST</SUP> WING R.A.F., MESOPOTAMIA" cachet in violet, F.P.O. 55 c.d.s. and London transit d.s., Army Post Office SZ10, Air Ministry and Paris d.s. on reverse. Photo | Christie's