Very interesting pair of covers commemorating the 50th anniversary of U.S. Air Mail Service linking Washington, New York, and Philadelphia.

Postmarked: 1) MC - WASHINGTON, D.C. - May 15, 1968
2) MC - PHILADELPHIA, PA - May 15, 1968

Both covers are backstamped NEW YORK, N.Y. on May 15, 1968, as shown above.

Cachet: 1) Maroon rubber-stamped design with text reading: "GOLDEN ANNIVERSARY . U.S. AIR MAIL SERVICE / AIR MAIL SERVICE WASH. N. Y. PHILA. / WASHINGTON / MAY 15 1918 FIRST TRIP
2) Greenish rubber-stamped design with text reading: "GOLDEN ANNIVERSARY . U.S. AIR MAIL SERVICE / AIR MAIL SERVICE WASH. N. Y. PHILA. / PHILADELPHIA / MAY 15 1918 FIRST TRIP

Condition: Generally neat and clean but with some ghosting of the backstamp cancellation ink on the Philadelphia cover. There's also faint evidence near the lower right corner that a small peelable address label was used on each cover.

MULTIPLE ITEM SHIPPING DISCOUNT: I will ship up to 4 covers for the single base shipping charge shown. (This lot includes 2 covers.) For purchases of more than 4 covers, the shipping charge will increase by just a small increment for every 4 additional covers.