And now, in the latest transition from science fiction to reality: the coming of "flying taxis." In just a few years, you might well see vehicles passing overhead, on their way to delivering passengers or packages in the same manner as earthbound taxis and vans. Uber, for one, is reported to be planning the launch of an air taxi service by 2020. The craft might even be pilotless, at the same time that driverless cars will be making headway on roads and highways. Among the pioneers of the air taxi concept is SkyRunner, developer of a military-grade utility vehicle that can take to the sky as a light sport aircraft (LSA). On this episode, we hear about the progress of the technology from SkyRunner chief executive officer Stewart Hamel. He talks about how such vehicles might transition from military use to commercial applications, as yet another means of solving the problem of the "last mile." But there are barriers to be overcome: logistics, regulatory and psychological. Hamel tells us how soon that's likely to happen.