Only four Army Air Service aviators received the Medal of Honor during World War I, half of them for one of the most famous episodes of that terrible conflict -- the rescue of the famous "Lost Battalion." Second Lieutenant Erwin R. Bleckley, a field artilleryman from the Kansas National Guard, was an aerial observer attached to the Air Service's 50th Aero Squadron. Bleckley and other Guardsmen had volunteered as individuals for aviation duty during the war. He and other members of the 50th Aero Squadron had been assigned to locate and resupply the 1st Battalion, 308th Infantry, 77th Division. That "Lost Battalion" had been completely cut off and pinned down in a deep ravine by German forces on October 3, 1918, while advancing in the Argonne Forest as part of General John J. Pershing's Meuse-Argonne offensive with 600,000 troops of the American Expeditionary Force. Having failed to locate the "doughboys" on their first mission of the day, Bleckley and his pilot, First Lieutenant Harold E. Goettler, had volunteered for a second. Flying barely above the treetops and steep ravines, they drew intense enemy fire while making several passes over the area where they expected to find the American troops. German machine gunners fired down at the flyers from the ridges above their fragile aircraft, as well as from below it. Badly wounded and with their De Havilland aircraft severely damaged, with at least 40 bullet holes in it, they made a forced landing near a French outpost. Goettler was dead when the French troops reached him. Bleckley died before the French could evacuate him to a medical aid station. However, his notes from the mission narrowed the search area where the trapped soldiers might be found. Each aviator received the Medal of Honor, posthumously, for his courage and sacrifice. Their mission underscored the critical importance of observation aviation to allied ground forces during World War I. Erwin Bleckley was the first of three National Guard aviators to receive the Medal of Honor during the twentieth century.