Not all UAVs:

http://en.wikipedia.org/wiki/Northrop_Grumman_X-47B

The X-47B receives commands from the flight deck, but is not directly piloted. It not only can be catapulted from an aircraft carrier, fly its mission, and return with no human input, it can also autonomously on-air refuel from a tanker with no human pilot on the ground.

<cynical thought>Remotely piloted by guys who aren't sitting at the pointy end of 100 tons of jetfuel doing 600mph, and therefore might not be quite as well motivated to succeed as their in-jetliner colleagues…