The X47B is a carrier based drone research aircraft. Autonomous refueling has huge potential for commercial airplanes. Long haul heavies and supers use 20% of their fuel to carry the fuel. Imagine the savings if they could meet a tanker enroute to take on enough to complete the flight. Perhaps a bit of the savings could be slipped in the pilots pay packet? (electronicdesign.com) さらに...
Keeping the fuel in the tanker aloft isn't free, and the heavy/super would either have to come to an orbiting tanker, or the other way around. You're only shifting the problem.
The tanker would take off and arrive at the predetermined location just in time for the flight to take a sip. The tanker Hobbs time would be quite low, on the order of 20 minutes. No circling, no waiting.