The Military Watch Magazine: The U.S. Air Force has deployed KC-135 and KC-46 Stratotankers across the Atlantic, with more than 30 deployed as of June 15.
It is believed that they could be used in an Israel-Iran war to refuel Israeli aircraft striking Iran, or to refuel American fighters and bombers if the U.S. becomes more involved in the war. The U.S. already supports Israel with THAAD air defense systems and AEGIS destroyers to intercept Iranian missiles.
Israeli F-15s can reach Iran without refueling, but the F-16s that make up the bulk of the fleet do not have that range, even with fuel tanks and long-range missiles.