It's happened six times over the last four days. Now, the FBI is investigating how laser beams have been directed into the cockpits of commercial airliners.
Agents are concerned that terrorists could use the lasers as weapons.
The bureau is looking into two laser beam incidents in Colorado Springs, one in Cleveland, and three others.
But a federal official says there's no proof of a plot or terrorist activity.
Two pilots reported green pulsating laser lights were beamed into their cockpits on approach to the Colorado Springs airport Monday night. A laser was also aimed into the cockpit of a commercial jet near Cleveland.
All of the planes landed without incident.
Interfering with flight crews is a federal felony offense.
Laser beams can distract or temporarily blind a pilot. In September, a Delta Air Lines pilot reported an eye injury from a laser beam shone into the cockpit during approach to Salt Lake City's airport. That plane landed safely.
Air traffic controllers in Cleveland used radar to determine that Monday's laser beam came from a residential area. Police responded in patrol cars and a helicopter, but could not determine the source.