Thailand. (Air Mail). 1926. Air Mail envelope addressed to 'Mr Boon-Thoung Ju-Phong-Saet, Postmaster, Ubon' bearing SG 244, 1t green and lilac tied by small 'aeroplane' date stamp of Nagor Rajasima '9th April 1926' with 'Mit Flugpost/ By Air Mail' label and bilingual Ubon arrival on face.
Nice usage of the Coronation Stone issue on the weekly flight of the 'Royal Aeronautical Service from Korat to Ubon.