The regulations address height and speed restrictions and other operational limits, such as prohibiting flights over unprotected people on the ground who aren't directly participating in the drone operation. For example, the drone may fly 400 feet above ground level, or, under the final rules, go higher than 400 feet if it remains within 400 feet of a structure. Initially, the FAA allowed drones to fly up to 200 feet, but earlier this year raised the ceiling to 400 feet.