The US military is quickly and quietly replacing aircrews with unmanned aerial combat vehicles
On August 10, 2005, two X-45A UCAVs took off, flew to a test range that had a "hostile" anti-aircraft system on it, destroyed it, and landed -- all on their own. The X-45As successfully detected the potential attack, took evasive action, and carried out their own attack, destroying the enemy anti-aircraft system. Although a USAF pilot on the ground monitored the sortie and could have inserted himselfm into the operation, the X-45As operated without any human intervention.
While AI (artificial intelligence) is still in its adolescence, the main purpose of the X-45A is to test and perfect the flight control and combat AI systems for the larger, X-45C UCAV, which will enter service with the US Navy and Air Force by 2010. The X-45A has a payload of 1.2 tons. The X-45C JUCAS (Joint Unmanned Combat Air System) will have a 2.2 ton payload and be about the size of an F/A-18 and is being built to handle in-flight refueling.
While UCAVs are being designed to deal with particularly dangerous missions, they can also be equipped for air-to-air combat. Though the flag officers in the USAF and USN are horrified at this prospect (think of "Top Gun" as the story of a guy who sits in a room and fights the enemy with an Xbox), UCAVs are seen as the solution to fighting a war without the American public screaming about losses of life. UCAVs are usually smaller and more maneuverable than a manned aircraft (no pilot to black out during high-G maneuvers) of the same general capabilities, making them harder targets to spot and kill. Aircrews -- especially aircrew of small crew tactical aircraft -- are watching this development with a combination of dread and resignation.
Look for the X-47 to begin replacing the F-16 and F/A-18 after 2010