For instance, Boeing Unmanned Systems (St. Louis) claims that its X-45A robot fighter can be built and operated at one-third the cost of the F-35 Joint Strike Fighter, a piloted fighter currently being developed by Lockheed Martin Tactical Aircraft Systems (Fort Worth, TX).

The X-45A was developed for the U.S. Air Force and the U.S. Defense Advanced Research Projects Agency. The 26-foot tailless aircraft recently completed a successful test flight, reaching an altitude of 7,500 feet. It has a 34-foot wingspan and weighs 8,000 pounds empty. The combat-ready aircraft will eventually carry up to 12 250-pound bombs at a top speed of 500 to 600 miles per hour and a cruising altitude of 35,000 feet. The Air Force expects to have a squadron of the UCAVs flying by 2007.

Northrup Grumman Integrated Systems (Dallas) is developing a UCAV for the U.S. Navy. The X-47A Pegasus is 28 feet long, with a nearly equal wingspan. It is shaped like a kite to incorporate stealth features. The unmanned, jet-powered weapon will be launched from aircraft carriers.

"UCAVs will effectively and affordably perform extremely hazardous missions, such as the suppression of enemy air defenses, while greatly reducing the risk our aircrews have to face," predicts Col. Michael Leahy, an Air Force officer who manages the X-45A program. At first, robotic aircraft will "ask" human controllers for permission to bomb targets.

Eventually, Leahy says UCAVs will be programmed to independently attack targets in designated "kill boxes" when an aircraft sees a target that matches its memory. In their initial deployments, as early as 2007, UCAVs will be used to attack enemy radar and antiaircraft installations.

A Pentagon planning document called Joint Vision 2020 forecasts that one-third of the U.S. military’s combat planes by that year will be robotic. Officials estimate that robotic aircraft will cost less than half as much as piloted fighters, largely because they lack humans. The Pentagon is considering UCAVs as a missile platform to intercept ballistic missiles in the early stages of launching.

Unmanned aerial vehicles transmit signals through high-bandwidth satellite relays to ground stations and piloted aircraft. The mission control console developed for the X-45A, for instance, allows an operator to control up to four aircraft simultaneously.

Military officials are keen on the future of robot planes, because unmanned reconnaissance aircraft, such as the Global Hawk and the Predator, have been successfully deployed in Afghanistan during Operation Enduring Freedom. For example, the Predator’s ground crews are feeding surveillance video and aperture radar data to hovering AC-130 gunships, allowing fresh targets to be fired on within minutes of sighting.

The Global Hawk is manufactured by Northrup Grumman, while the Predator is made by General Atomics Aeronautical Systems Inc. (San Diego). Ground-based pilots in a control van use a yoke, stick and rudder to fly the Predator. The Global Hawk is an autonomous UCAV that takes off and lands itself. Specialists program an onboard computer that controls the aircraft flight from point-to-point. Both aircraft use sophisticated sensors and logistical equipment. However, the pricetag of one Global Hawk, which includes related ground-control stations, is almost as much as much as two manned F-16 fighters.

Frost & Sullivan Inc. (San Antonio, TX) predicts that the worldwide market for unmanned aerial vehicles (UAVs) will reach $5.6 billion by 2007. Boeing claims the market for robotic aircraft will reach $10 billion by the end of the decade.

"The potential uses for UAVs outside the military are numerous and increasing," says Quinton Long, an aviation industry analyst at Frost & Sullivan. "UAV applications are set to explode in the commercial market once airspace regulations are defined and published." Potential applications include robotic cargo planes. "Currently, the complexity of controlling airspace shared by both manned and unmanned systems presents a thorny barrier to the civilian UAV market segment," Long points out.