Range anxiety, the bugaboo of all-electric driving, is even more frightening for all-electric flying, where running out of power has worse consequences than having to pull over to the side of the road. A solution now comes from Workhorse, an Ohio-based firm. It has a passenger-carrying air taxi, called the SureFly, which combines the company's expertise in partially automated operation, from its drone business, and in hybrid-electric propulsion, from its truck business. The craft's eight counter-rotating motors each drive a carbon-fiber rotor, and the power comes from a generator cranked by an internal-combustion engine. You can fly 110 kilometers (70 miles) on a tank, then refill in minutes.