2c red postal stationery envelope (H&G B13) used with added 1928 25c on 10c orange AIR surcharge issue (SG 224) tied by undated AGENCIA POSTAL PRIMER CORREO AEREO INTERNACIONAL PANAMA R.DE P. cancels and by PANAMA cds dated FEB 9 1929. Sent registered on the PANAMA - MIAMI 'LINDBERGH' escort flight with boxed registration marking and straight line PANAMERICAN AIRWAYS PRIMER VUELO cachet in purple. Addressed to USA with transit and arrival marks on reverse. (Muller #8a)