The U.S. government has agreed to support the Saudi-lead air campaign in Yemen by providing aerial refueling tankers.
“168th Air Refueling Squadron – Boeing KC-135R Stratotanker 63-8876 – 2” by United States Air Force – http://www.168arw.ang.af.mil/photos/mediagallery.asp?galleryID=6158&page=2. Licensed under Public Domain via Wikimedia Commons.