 Complete the following phrase:  Since then, the KC-10 had participated in other smaller conflicts. In March 1999, NATO launched Operation Allied Force against the government of Yugoslavia. The mobility portion of the operation began in February and was heavily dependent on tankers. By early May 1999, some 150 KC-10s and KC-135s deployed to Europe where they refueled bombers, fighters and support aircraft engaged in the conflict. The KC-10 flew 409 missions throughout the entire Allied Force campaign and continued support operations in Kosovo. Since 11 September 2001, KC-10s had also flown more than 350 missions guarding U.S. skies as a part of Operation Noble Eagle. During 