World War I, U.S. Air Operations in. The U.S. declaration of war on April 6, 1917, found American aviation in an embryonic and woefully unprepared state. The army air service had some 1,400 officers and men; naval aviation, 300.

America's first operational unit in Europe, a naval air detachment, began flying seaplane escort for French coastal convoys in September. The first army flight candidate landed in France in June 1917, while those arriving in Italy in the fall included New York congressman Fiorello La Guardia.

In France the command of the embryonic U.S. Air Service remained in flux into 1918, as frontline commander Col. William “Billy” Mitchell emerged as the key leader. Mitchell determined to undertake a tactical aerial offensive on the Western Front with an air arm of new recruits from America and a nucleus of veterans from the Lafayette Escadrille and Lafayette Flying Corps, who had flown with the French since the battle of Verdun in 1916.

U.S. units entered action in the quiet sector around Toul in the spring, and in early June thirteen squadrons joined the struggle over Chateau‐Thierry during the Aisne‐Marne offensive.

When the First Army AEF attacked the St. Mihiel salient on September 12 to 16, Billy Mitchell commanded 1,481 airplanes, the largest wartime concentration of Allied air forces, nearly half of which were American. Despite poor weather conditions, this overwhelming mass seized aerial control as fighters penetrated over German airfields and day bombers struck targets on the battlefield and in the rear. St. Mihiel also marked the meteoric ascent of balloon‐busting ace Frank Luke, who shot down 18 Germans in 17 days before meeting his death. The impetuous Luke won the Medal of Honor, as would American ace of aces Eddie Rickenbacker, who ultimately gained 26 victories and survived the war.

In the climactic Meuse‐Argonne Offensive from September 26 to the end of October, Mitchell successfully continued his massed offensive tactics. By the Armistice the intensive fighting combined with supply problems to reduce the air service to 45 squadrons with 457 serviceable airplanes, nearly two hundred fewer aircraft than in September. Yet the air service had grown to 195,024 officers and men by war's end. More than 2,000 American flight personnel had reached the front. 681 aviators died, 75 percent of them in accidents and 25 percent in combat.

By October 1918 the navy had some 900 seaplanes for convoy duties, 400 of which were stationed abroad at 27 U.S. naval air stations from Ireland to Italy. A few naval aviators flew bombers from Calais‐Dunkirk, while army aviators in Italy manned bomber units there.

American industry delivered Curtiss flying boats, the standardized Liberty engine, and copies of the British DH4 bomber to American combat units. Yet inadequate overall aviation production necessitated American reliance primarily on allied aerial equipment. The U.S. Air Service's significance lay in its support of the army through reconnaissance and attacks on enemy troops and supplies at and behind the front, while fighter aviation protected observation and bomber craft, engaged in ground attack, and provided the public with heroic aces.
[See also Air Force, U.S.: Predecessors of, 1907 to 1946; Strategy: Air Warfare Strategy; World War I (1914–1918): Military and Diplomatic Course.]

Bibliography

James J. Hudson , Hostile Skies: A Combat History of the American Air Service in World War I, 1968.
Adrian O. Van Wyen , Naval Aviation in World War I, 1969.

John H. Morrow, Jr.