The Pentagon is considering using lasers to warn pilots they've flown into restricted airspace.
The Colorado Springs-based North American Aerospace Defense Command has been researching the use of alternating red and green lasers as a way to communicate with pilots flying too near the Capitol or the White House when they can't be reached by radio.
If the system becomes operational, the Federal Aviation Administration would send a special notice to pilots describing the lights and telling them what to do if they see them.
But the choice is unusual because the government also says terrorists might use the beams of light to blind pilots as they approach airports. NORAD says its low-intensity lights are safe for the eyes.
Beginning in December, the FBI investigated a rash of incidents around the country in which lasers were shone through cockpit windows, including two such instances in Colorado Springs. Though no links to terrorism were found, the government said in January it would require pilots to report immediately any lasers beamed at airplanes.