Members of the 131st returned in October 2000 from duty rotations in Southwest Asia and Europe, while other unit members were still stationed overseas. Eventually, a total of about 430 wing members were scheduled to deploy, with the majority leaving in October 2000 for Prince Sultan AB, Saudi Arabia, in support of Operation Southern Watch. A little more than half of the deployed 131st Fighter Wing members and 12 F-15s made up the AEF-9's 110th Expeditionary Fighter Squadron (EFS). The 110th EFS primarily provides air superiority for Operation Southern Watch. AEF-9 was deployed from September through November 2000. In 2004, the improved F-15C Eagle arrived, replacing the older aircraft.