IX Air Defense Command was established in the ETO to carry out Air Defence, it over saw fighter aircraft, anti-aircraft artillery and signal warning units.



In 1943 the War Department determined air defence to be the responsibility of the US Army Air Forces. The 9th Air Force drew up a plan for an Air Defence Command in late 1943 and set up a head quarters using personnel form the 51st and 52nd Anti-Aircraft Artillery Brigades, and from the 118th Anti-Aircraft Artillery Group. The organisation was then officially announced on 30 March 1944 under the Command of Brigadier General William L Richardson



In January 1944, IX Air Defense command coordinated the defence of Ninth Air Force and Communications Zone installations during operation Overlord. This was combined with the training of air, Anti-aircraft artillery and signal troops in the performance of their air defense missions.



During February and March, antiaircraft units in increasing numbers began to arrive in the United Kingdom and a number of them were attached to the Command and used to defend Ninth Air Force operational airfields. Other AAA units were given additional combined training

with air force units, while AA personnel trained 9th Air Force Ground Crewmen on how to use Anti-Aircraft guns, to supplement the defence of airfields.



The command was formerly established in July 1944, and activated on 1 July 1944, where its mission changed to to provide air defense for liberated areas of Western Europe consisting of France and later, the Low Countries. In addition to their air defence duties, the command saw it's units engaged in combat at St Lo in July 1944, undertook attacks on retreating tanks, trucks, and troop concentrations and provided armed reconnaissance for advancing Allied armored columns.



In September 1944, the units of the command attacked flak positions near Eindhoven during Operation Market-Garden, and bombed enemy communications and transportation lines in western Germany. The flying units also flew armed reconnaissance missions over Battle of the Bulge during December 1944 – January 1944 and missions against enemy transportation systems including motor vehicles, bridges, trains, railway bridges, and marshalling yards during February and March 1945.



The Command finally moved to Germany in April 1945, flying last combat missions on 3 May 1945.