Photos: Keeping watch with unmanned aircraft

This slender-wing aircraft is the Altair UAV, which had its checkout flight in June 2003 at El Mirage, Calif. The Altair was developed for NASA by General Atomics Aeronautical Systems for long-endurance, high-altitude missions. It will be used to test collision-avoidance technologies that are necessary for UAVs to fly in the U.S. national airspace--and share skies with general aviation pilots and commercial flights.

Photo by NASA