The Wisconsin Air National Guard origins date to 30 July 1940 with the establishment of the 126th Observation Squadron and is oldest unit of the Wisconsin Air National Guard. It is one of the 29 original National Guard Observation Squadrons of the United States Army National Guard formed before World War II. The 126th Observation Squadron was ordered into active service on 2 June 1941 as part of the buildup of the Army Air Corps prior to the United States entry into World War II.