Thailand. (Air Mail). 1925. Air Mail envelope hand-stamped 'By Air Mail' addressed to Ubol, Siam bearing SG 232, 5s green and SG 234, 15s carmine tied by small 'aeroplane' date stamp of Uttara '10th Feb 1925' with Ubol arrival '17/2' on face and reverse.
Carried in the weekly flight of the 'Royal Aeronautical Service from Uttara to Korat and on by train.