The Lockheed Martin RQ-170 Sentinel drone is a stealthy unmanned aircraft that has been loitering in Pakistani airspace and collecting all kinds of intelligence including serving as a critical relay station the night Navy SEAL Team 6 killed Osama bin Laden. Details are sparse on the still-classified flying-wing craft, with estimates of its wingspan ranging from 60 to 90 feet. Nicknamed the "Beast of Kandahar" for sightings of the drone at the Afghan airbase, the Air Force RQ-170 has the ability to send imagery from the theater all the way back to Washington. Given the fact that the enemy in Afghanistan has no air defenses, sending a stealthy platform to the country was a clear suggestion its intended use was over Pakistan. It's a decent bet that some of the video President Obama and his national-security team were viewing in the White House situation room on the night of the May 2, 2011 of the raid on Osama bin Laden's Pakistan lair was courtesy of an RQ-170.
For the inside story on America's military operations around the world, check out Mark Thompson's blog, Battleland: Where military intelligence is not a contradiction in terms.