To the anons on previous bread tracking the KC-10's headed up the coast and wondering why they were so close together, the KC-10 is capable of being refueled in flight. It's the only air refueling tanker we have with this capability. The KC-135 can refuel other aircraft but it cannot be refueled in flight.
So that flight is most likely a training sortie where they take turns on the boom practicing being refueled.
Don't be a lameplanefag and post stuff like this. Be a smartplanefag and dig on these aircraft, especially the military aircraft, and make reasoned assessments as to why they might be doing this.