The first USAF E-4B serviced at Boeing’s San Antonio site was serviced and returned to duty ahead of schedule in May 2015.. Boeing also performs maintenance on Air Force C-17 Globemaster III airlifters, KC-135 aerial refueling tankers and on commercial aircraft at that site.

Based on the Boeing 747-200 commercial airplane, the E-4B’s primary role during a conflict is as an airborne command post under the direction of the president, secretary of defense and the Joint Chiefs of Staff.

Boeing built the E-4 fleet and, with the Air Force, has supported the aircraft since the program’s launch in 1974. The company is on contract to maintain the readiness of the aircraft’s systems, bringing each aircraft in for service every two years.