<p>Completing the combat support force are the tankers. Inflight refueling of combat aircraft allows the US Air Force to project its power to any point on the globe, and is vital to the ability of its aircraft (which are being increasingly based within the United States itself) to deploy overseas at short notice. Combat operations can be conducted across far greater ranges than are possible without tanker support.
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<p>A massive fleet of Boeing KC-135 Stratotankers is augmented by the McDonnell Douglas KC-10 Extender, and the operations of both are increasingly being interwoven with tactical aircraft to provide greater flexibility of response to any crisis that may arise. The KC-10s are relatively new, but the KC-135s are anything but, and are the subject of a major updating program that replaces old 1950s-vintage turbojets with modern turbofans to increase the aircraft's effectiveness and reduce operating costs.
