when the united states entered world war i in april 1917, the war department decided that it would not mobilize national guard air units. instead, individual guard volunteers provided a major pool for the army to draw aviators from. they were required to leave the guard and enter the signal corps reserve if they wished to fly in the war. about 100 national guard pilots joined the newly formed united states army air service. guardsmen also played prominent roles in air operations in france. on 14 april 1918, tennessee guardsman reed chambers flew with eddie rickenbacker and david peterson of the 94th pursuit squadron from villeneuve, france on the first combat mission ever ordered by an american commander of a u.s. squadron of american pilots. at least four guardsmen—chambers, field kindley (kansas), reed landis (illinois), and martinus stenseth (minnesota) – became aces. 2d lieutenant erwin r. bleckley of kansas was awarded the medal of honor posthumously for his heroism as an aerial observer. after the armistice and the return of the american expeditionary force in 1919, the wartime squadrons were demobilized and inactivated.