Aviation Meet post card
Hamilton (Ohio) Retail Merchants Association sponsored the Butler County Fair Aviation Meet, held from July 12-13, 1912. Charles F. Walsh flew mail each day from the meet to Krebs Baseball Park, where he dropped it to waiting postal officials. The Post Office Department designated the flights as Route No. 631,002. Approximately 1,250 pieces of mail were flown on July 12 and about 1,000 on July 13. Mail of July 12 is seldom seen.
Walsh carried this post card on July 13, 1912. It bears a black, three-line postmark that reads, "AERO MAIL SERVICE / JULY 13 1912 / HAMILTON, OHIO." A six-line killer bar cancels the 1-cent Washington stamp.