The many use cases for drones are now clear. They can help tend crops more efficiently, find people lost in the wilderness, and even carry packages. How drones can be widely used for such things safely is much less certain.
The U.S. Federal Aviation Administration says it won’t allow small drones to go beyond their pilot’s line of sight until technology is developed that allows the small fliers to detect and avoid other aircraft. That restriction would ground ideas like Amazon and Google’s plans for package delivery and make many others less lucrative.