Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - United States - 1911, three black-and-white PPC commemorating Air Meet in Chicago, representing Mercury Biplane preparation for flight, Mercury Biplane in flight and wreck of Mercury Biplane, two sent from Chicago in 1911 and the last one in August 1913, franked by Franklin or Washington 1c green, mostly VF, Est. $300-$400, Sc. # 331, 405