Registered cover franked with 1924 pair 2c carmine and 5c blue 'Arms' issue and 1928 25c on 10c orange AIR surcharge issue (SG 200/201 & 224) tied by undated AGENCIA POSTAL PRIMER CORREO AEREO INTERNACIONAL PANAMA R.DE P. cancels with boxed registration marking alongside. Flown on the Panama - Miami 'LINDBERGH' escort flight. Addressed to USA with transit and arrival marks on reverse. (Muller #8a)