Thailand. (Air Mail). 1925. Air Mail envelope with bilingual hand-stamp 'By Air Mail' in violet addressed to 'Chan Chin Foo, Bangkok' bearing SG 231, 3s brown, SG 232, 5s green and SG 234, 15s carmine tied by small 'aeroplane' date stamp of ROI ETCH dated '17th March 25' with Bangkok 'aeroplane arrival '20/3' on reverse and adjacent Bangkok/ 2 date stamp.
C.J. Chan, stamp dealer and philatelic writer applied his own hand-stamp on the weekly flight of the Royal Aeronautical Service from Roi Et to Korat and further by train to Bangkok.