I was out shooting in the local dunes some years back. The area is on a flight path...Airplane Hill still has a rusted aircraft engine lying on it,..and I heard something coming in. I turned and saw a KC-135 coming in very low. Pretty impressive, for this area. I’d occassionally seen them refueling fighters out alonfg the coast, and once saw what looked like one refueling another -135.
It was probably refuelling an E-8 JSTARS. It is also based on the 707 airframe although larger than a KC-135.