Developing an aircraft that stays airbourne for 5 years

In 2008 Technovelgy reported that Defense Advanced Research Projects Agency (DARPA) is developing an unmanned aircraft that is heavier than air, will carry a payload, will remain in air for over 5 years (ultra-long endurance) and is not nuclear powered. Since it sounded more like science fiction than reality, it was not taken seriously. Now, 1.5 years later, the program not only appears to be on track but FlightGlobal quotes Dan Newman, Vulture program manager at DARPA that the Vulture program will revolutionise the way the US military acquires, builds and operates an aircraft reports. Surprisingly, he thinks that if this revolutionary concept is proved there would be resistance from the military and little support from politicians.