Flying Exhibition postal card
Benton Harbor, Michigan, hosted its Fair Grounds Flying Exhibition from July 17-18, 1912. Charles F. Walsh flew a bag of mail each day from the fair grounds to a point near the post office, a distance of about two miles. The Post Office Department assigned this route No. 637,001. Walsh flew about 500 pieces of mail on July 17 and about 700 pieces the next day. The Aero Mail Club, predecessor of the American Air Mail Society, sent its 1912 membership cards via these flights.
Walsh carried this card, addressed to collector Karl Koslowski, Detroit, on July 18. The large, circular postmark reads, "BENTON HARBOR, MICH. / JULY 18 / 1912 / FAIR GROUNDS STATION." Straightline killer bars with the words "VIA AEROPLANE TO MAIN OFFICE" cancel the 1-cent McKinley indicia.