Westover Air Reserve Base is an Air Force Reserve Command (AFRC) installation located in the Massachusetts communities of Chicopee and Ludlow, near the city of Springfield, Massachusetts. Established at the outset of World War II, today Westover is the largest Air Force Reserve base in the United States, home to approximately 5,500 military and civilian personnel, and covering 2500 acres (10 km²). Until 2011, it was a backup landing site for the NASA Space Shuttle and in the past few years has expanded to include a growing civilian access airport sharing Westover's military-maintained runways. The installation was named for Major General Oscar Westover who was commanding officer of the Army Air Corps in the 1930s.

The Air Force Reserve Command (AFRC) is a major command (MAJCOM) of the United States Air Force, with its headquarters at Robins Air Force Base, Georgia. It is the federal Air Reserve Component (ARC) of the U.S. Air Force, consisting of commissioned officers and enlisted airmen. Together, the Air Force Reserve and the Air National Guard constitute the Air Force element of the reserve components of the United States Armed Forces. AFRC also plays an integral role in the day-to-day Air Force mission and is not strictly a force held in reserve for possible war or contingency operations. AFRC also supports the United States Space Force through the 310th Space Wing, pending the creation of a space reserve component.