Reports of drone sightings near other planes, helicopters and airfields are reaching the government almost daily, say federal and industry officials.
The FAA requires that drone and model aircraft operators keep flights to under 400 feet in altitude, keep the aircraft within sight of the operator and stay at least 5 miles away from an airport. Small drones are often indistinguishable from model aircraft, which have grown in sophistication.
Commercial operators and government officials from police to research scientists must obtain FAA certificates of authorization to fly drones. Exceptions are made for some government drones such as those the military flies in great swaths of airspace in reserved, remote areas. Customs and Border Protection flies high-altitude drones along the U.S. borders with Mexico and Canada.