A drone taken over by hackers can turn from an efficient flying tool into a dangerous machine. Once under rogue control, it may fly unpredictably, slow down, reverse direction, or crash. When that ...

Unmanned aerial vehicles, or drones, are no longer the amateur toys they used to be. They’re now lifelines for industries ranging from agriculture and construction to defense and emergency response.

“It often makes sense to buy rather than build,” said Brandon Tseng, Shield AI’s president and cofounder. (Frank Bajak/Associated Press) Defense-technology firm Shield AI said it is buying an ...