The 108th ARS is the flying component of the 126th ARW and has operated the KC-135E since 1983. The unit was activated in July 1927 and called up from February 1941 until November 1943. It was federalized in January 1947 with the A-26 as the 108th Bombardment Squadron at Chicago Municipal Airport, and mobilized again in April 1951 during the Korean War. The squadron returned to state control and was redesignated the 108th Fighter-Bomber Squadron with F-51Ds, and moved to O'Hare Airport in April 1954. The unit converted to the F-84F in July 1955 with a change to Fighter-Interceptor Squadron status. The squadron became the first ANG air refueling unit, in July 1961, with the KC-97F assigned, and subsequently upgraded to KC-97L before converting to the KC-135A in December 1976. The unit has moved to Greater Rockford Airport.