For reference, the thirty or so aerial-refueling tankers deployed last night to Europe, are less than 10% of the U.S. Air Force’s fleet of KC-135s and KC-46s. The United States has more aerial-refueling aircraft than all other countries in the world combined, and this doesn’t even include other aircraft that can be converted for aerial-refueling, like the F/A-18E Super Hornet.