In college, my university did a lot of research in regards to UAV's. And I have one foolproof prediction to make.

No commercial aircraft will fly without a pilot for at least the next 100 years. Period. Computers can't deal with emergency situations. Passengers will not feel safe. This will not happen in our lifetime.

The trend with computers is to make flying more automated, and reduce the workload of the pilots. In the past, we have seen computers replace the flight engineer position. Three pilots down to two. But pilots will not suddenly disappear from the cockpit. I think that if automation gets real good, you may be able to see a single pilot in charge of a commercial aircraft. But the day a computer is the pilot in command of an airliner carrying 300 passengers will not come in the next 100 years. It will not be allowed by the flying public.

As for UAV development, they are a real benefit in military combat. But I see no benefit for UAV's in the civilian world. For those AOPA members, you know that AOPA has been fighting with the FAA over TFR's around the Mexico border because of UAV operations. Why a TFR? Because UAV's currently have no way of seeing and avoiding VFR or IFR air traffic. Why these UAV's are even being used in US airspace is beyond me. It is cheaper to get a Cessna-182 and pay a pilot to fly the route, rather than pay the operating costs of the UAV's. Plus a pilot in a 182 would be a lot safer and more convenient for other general aviation traffic. UAV's should be restricted to military combat. Reconaissence, and possibly aerial bombing.
Other than that, they do not have a practical use.