Drones. These unmanned flying robots -- some as large as jumbo jets, others as small as birds -- do things straight out of science fiction. Much of what it takes to get these robotic airplanes to fly, sense and kill has remained secret. But now, with unprecedented access to drone engineers (including a rare interview with the "Father of the Predator," Abe Karem) and those who operate drones for the U.S. military, NOVA reveals the amazing technologies that make them so powerful. Discover the cutting-edge technologies that are propelling us toward a new chapter in aviation history.