On CBS’ 60 Minutes, Amazon CEO Jeff Bezos announced a plan to deliver packages within 30 minutes by unmanned aerial vehicles, or drones. Amazon’s “Prime Air’ service could be used for packages which weigh less than five pounds, and can only be sent to destinations that are within 10 miles of an Amazon distribution center. Bezos said he hopes the service could be ready in four years. “I know this looks like science fiction,” Bezos said. “It’s not.” So, how realistic is this idea?