Cover franked with 1924 10c carmine & 50c black & orange (SG 300 & 302) tied by three strikes of PORT-AU-PRINCE cds dated 13 DEC 1927 with circular 'AVION' Airplane cachet in blue alongside. Flown on the Haiti - Puerto Rico first flight by pilot Basil Rowe with three line 'WEST INDIAN AERIAL EXPRESS INAUGURATION REP. DOMINICAINE.. CUBA.. PTO RICO.. HAITI' first flight cachet in blue on front. Addressed to PUERTO RICO with arrival cds and additional first flight cachet in green on reverse. (Muller #12, 1307 covers carried)