Federal Aviation Administration under pressure to open US skies to drones

The Federal Aviation Administration has been asked to issue flying rights for a range of pilotless planes to carry out civilian and law-enforcement functions but has been hesitant to act. Officials are worried that they might plow into airliners, cargo planes and corporate jets that zoom around at high altitudes, or helicopters and hot air balloons that fly as low as a few hundred feet off the ground.

On top of that, these pilotless aircraft come in a variety of sizes. Some are as big as a small airliner, others the size of a backpack. The tiniest are small enough to fly through a house window.

The obvious risks have not deterred the civilian demand for pilotless planes. Tornado researchers want to send them into storms to gather data. Energy companies want to use them to monitor pipelines. State police hope to send them up to capture images of speeding cars' license plates. Local police envision using them to track fleeing suspects.

Like many robots, the planes have advantages over humans for jobs that are dirty, dangerous or dull. And the planes often cost less than piloted aircraft and can stay aloft far longer.

"There is a tremendous pressure and need to fly unmanned aircraft in (civilian) airspace," Hank Krakowski, FAA's head of air traffic operations, told European aviation officials recently. "We are having constant conversations and discussions, particularly with the Department of Defense and the Department of Homeland Security, to figure out how we can do this safely with all these different sizes of vehicles."

There are two types of unmanned planes: Drones, which are automated planes programmed to fly a particular mission, and aircraft that are remotely controlled by someone on the ground, sometimes from thousands of miles away.