PANAMA: ZONA DEL CANAL. 1918 (18 Oct.). CORREO AEREO. CANAL ZONE AIRMAIL. First flight from the Atlantic to the Pacific (Cristobal to Balboa) with 1915 C.Z. 10 c. with special cancel and arrival marking. The cover was sent by W.L. HOWARD. One of only around a dozen non-Liberty Loan franked covers that were flown. Rare (Muller 25.000 ptas). (Image1)

€500