The Twenty-First Air Force is an active numbered air force of the United States Air Force. It was reactivated on September 5, 2025 during a ceremony hosted at the McGuire AFB entity of Joint Base McGuire-Dix-Lakehurst. It had been inactive since 2003, when it was previously designated as the 21st Expeditionary Mobility Task Force, headquartered at the McGuire AFB entity of Joint Base McGuire–Dix–Lakehurst until its inactivation in 2012. In this capacity, it was subordinate to Air Mobility Command's Eighteenth Air Force.