Drones as missle defense?

That costs thousands of dollars per hour to fly and probably a million dollars to fire.

"A billion here, a billion there, pretty soon, you're talking real money."
~anonymous (often missattributed to Everett Dirksen)

Sure, it's expensive as $#@!, but can you really put a price tag on awesome?

I was thinking of more off shore activity. Maybe a large craft like S.H.I.E.L.D.s helicarrier. Drones would dock and recharge and refuel then fly out to protect the coast from fifty miles out. I'm not sure about the laws regarding international waters though.

And then someone will inevitably hack them and do something dastardly with them.

The Air Force version may be on hold for now, but it's Naval cousin seems to be moving toward deployment:
The future is now: Navy to deploys lasers on ships in 2014

We're still a few years away from an energy weapon with the kind of power to take down all threats, but it's nice to see the DoD and the US Navy taking this technology to the next level. Give it another few decades and we'll be protected by swarms of laser-wielding autonomous drones on land, sea, air and even space... there's no way that could end badly.

I will point out that Missiles are Drones, albeit single use, and highly specialized. So are Satellites, so our missile defense has been Drone based for decades, pretty much since we went from AAA guns to Satellite Tracking, ManPADs, and heavier counter-missiles.

As for Drone Fighters, I would probably make them hypersonic, and missile carriers themselves barring any DEWs. (The Raptor Radar could be adapted to make re-usable missile/drones.) This is mostly to make up for the extreme speeds of missiles, and G forces from maneuvers that would kill an onboard pilot. I envision something not unlike the X-15, gutted, retrofitted with onboard navigation, RADAR/EMP, and targeting softwear. All Science Fiction, mind you.