First Flight cover with typed 'PAR AVION FIRST FLIGHT AIR MAIL GUATEMALA CITY TO SAN SALVADOR' at top franked with 1929 pair 2c bright blue and 1928 15c on 15p black TRAIN issue (SG 229 & 241) tied by boxed CORREO AEREO INTERNACIONAL 16 MAR GUATEMALA, C.A. cancels. Flown on the GUATEMALA - EL SALVADOR First Flight by PAA with boxed PRIMER ENVIO POSTAL AEREO DE GUATEMALA A CENTRO, SUD - AMERICA Y ANTILLAS 16 DE MARZO DE 1930 'Airplane' cachet in red on front and SAN SALVADOR arrival cds on reverse dated the same day. 387 covers flown. (Muller #18, Goodman #AM22f)