1919 First Flight - Honolulu to Hilo by U.S. Army plane. Cover addressed to Hilo, franked with 1¢ Wash-Frank pair + 10¢ Special Delivery tied by "Honolulu, Hawaii, Jul 3, 1919" duplex cancels, red manuscript "Via Airplane" endorsement at left, Very Fine, a rare Hawaii inter-island first flight usage, reputed to be only ten such usages known. AAMC No. 532A. Estimate  $500 - 750. $0 (Image)