Electronics has already cut the data cord. Can it now cut the power cord as well?
Jun 27th 2015 | Seattle | From the print edition
DRONES may one day transform the way parcels are delivered, crops monitored and suspects apprehended. Those who talk up these possibilities, though, often neglect to mention the drawbacks of such robot aircraft—one of which is that most cannot fly for more than a quarter of an hour before they need to find a human being to swap their batteries for them or plug them into an electrical socket.