While the U.S. Navy often depends on U.S. Air Force KC-135 aerial tankers to refuel its aircraft, it has sometimes also found it more convenient to use a civilian firm, Omega Air, to provide aerial refueling service in the United States. The air force controls all the large tankers (the navy can use some smaller aircraft, even fighters, for refueling in a pinch) and makes them available to the navy and other foreigners only when the air force has taken care of its own needs. Thus, non-air force users must sometimes wait. Omega Air allows the navy to avoid the wait.
Omega uses two Boeing 707s (the civilian version of the KC-135) and a converted DC-10 to refuel in the air and delivers fuel at less than half of what it costs the air force (about $5 dollars a liter/$20 a gallon using KC-135s and KC-10s). Some other countries also outsource for some of their aerial refueling needs. The navy has been using Omega since 2001, as have some foreign air forces. The navy keeps renewing the Omega contract each year, indicating satisfaction with the arrangement. The navy uses Omega a lot for training exercises or long distance movement of combat aircraft that would be a hassle to reschedule if the air force tankers were delayed because of air force refueling needs.