The Seventeenth Expeditionary Air Force was a numbered air force of the United States Air Force located at Ramstein Air Base, Germany. The command served the United States Air Forces in Europe during (1953–1996) and United States Air Forces Africa during 2008–2012. Upon reactivation on 1 October 2008, it became the air and space component of United States Africa Command. In this capacity, Seventeenth Air Force was referred to as U.S. Air Forces Africa (AFAFRICA). 17 AF was reformed in April 2012 to become the 17th Expeditionary Air Force, sharing a commander and headquarters with the Third Air Force. As of March 2022, the Third Air Force is USAFE-AFAFRICA's sole numbered air force, with the 17 EAF having been inactivated in July 2018.

A Numbered Air Force (NAF) is a type of organization in the United States Air Force that is subordinate to a major command (MAJCOM) and has assigned to it operational units such as wings, squadrons, and groups. A Component Numbered Air Force (C-NAF) has the additional role as an Air Force Component Command exercising command and control over air and space forces supporting a Unified Combatant Command. Unlike MAJCOMs, which have a management role, a NAF is a tactical organization with an operational focus, and does not have the same functional staff as a MAJCOM. Numbered air forces are typically commanded by a major general or a lieutenant general.