Printed 'American Consular Service' cover franked with 1929 3c purple, 1930 6c red AIR issue & 1927 1c olive green TAX issue (SG 230, 223 & 254) tied by COBAN ALTA VERAP cds dated 28 JUN 1930. Flown on the inaugural flight for the COBAN - GUATEMALA CITY domestic route with boxed 'INAUGURACION DEL CORREO AEREO DE COBAN A GUATEMALA' cachet in blue with 'Coban' inserted in manuscript and 'SERVICIO EXPRESO' marking alongside. GUATEMALA CITY transit and arrival cds's on reverse. (Muller #36a, Goodman #AM28b)