Photos: Keeping watch with unmanned aircraft

The Air Force describes the Predator UAV as a "medium-altitude, long-endurance, remotely piloted aircraft." It can carry two laser-guided Hellfire anti-tank missiles. It's been used on air strikes against suspected terrorists in Afghanistan and Pakistan. Cruising speed is 84 mph with an endurance of 16 to 40 hours.

Photo by U.S. Air Force