1961 REGISTERED AIR LETTER MOBILE POST OFFICE 'OXFORDSHIRE SHOW' TO USA. Fine QEII 6d carmine air letter to USA uprated with Wilding 6d x 3 cancelled neat strikes 'MOBILE POST OFFICE NO.3' date stamps 9 MY 61 from the Oxfordshire show. At upper left unappropriated registered label with ms 'Oxfordshire show'. On reverse USA receivers. (Ref 118295).