Uninhabited Aerial Vehicles, or UAVs, are taking to the skies as military and civilian organizations turn to remote-operated planes or helicopters to perform tasks considered dull, dirty or dangerous.

Already, drones have dropped bombs in the Middle East, snapped images of dangerous terrain from thousands of feet in the air and monitored traffic on congested roads.

Some commentators have even suggested that Lockheed Martin's high-tech F-35 Joint Strike Fighter may be the last inhabited fighter plane needed. At the very least, analysts say, drones can be used for potentially dangerous environmental monitoring, such as checking air quality for chemical and biological weapons.

``It's no longer 'yes or no' -- the technology and the systems are accepted,'' says Daryl Davidson, executive director at the trade group Association for Unmanned Vehicle Systems International (AUVSI). ``These things are here to stay and they are proliferating.''

Proliferating, yes, but not without doubts about their ability to operate safely over urban centers, their cost, and a crash rate that for some far outstrips fighter jets.

In addition, uninhabited vehicles demand extremely high bandwidth -- a measure of how much information can be carried at any given time -- so their use is limited until the technology catches up with the inspiration.

Most fears center on their safety for civilian use, such as monitoring traffic over urban areas.

``They don't have a pilot to get them out of trouble,'' notes Steve Zaloga, an analyst with Teal Group, an aerospace and defense research firm. ``The local TV station isn't going to be happy to have a million-dollar plane crash into traffic or someone's house. It's going to be a hazard and it's going to be a cost issue.''

DRONES

The use of drones took off during the Vietnam War, when soldiers strapped cameras onto target planes and flew them remotely through high-threat areas.

But real leaps have come recently amid breakthroughs in technology, Defense Secretary Donald Rumsfeld's clarion call for military transformation, and their success in action in the Balkans and elsewhere.

Advances in satellite-guided global positioning systems and wireless communications have helped scientists jump numerous hurdles.

Networking technology and increasing bandwidth, too, have driven invention, since they allow the complex machines to communicate simultaneously with centers that send them directions, as well as other locations to which they beam their images.

These innovations have led to the development of combat UAVs like Boeing's formerly top-secret X45 plane, which can carry at least 1,000 pounds of precision-guided bombs and be either pre-programmed on the ground or have its mission plan changed mid-flight.

If operations go as hoped in 2006, the Department of Defense will start fielding the systems in 2008, Boeing says.

The Marine Corps has also been testing 5-pound, backpack-portable UAVs called Dragon Eye for ``over-the-hill'' reconnaissance. Missions are programmed via wireless modem and the planes can be launched by hand or bungee cord.

The Marines plan to field at least 311 in coming years. Drones' successes at reconnaissance and bombing in Kosovo, Afghanistan and Iraq have also garnered support for the technology.

``Much to the chagrin of fighter pilots in the Pentagon, UAVs are here to stay,'' says John Kutler, an industry watcher and chief executive of U.S.-based defense investment bank Quarterdeck Investment Partners.

Combat drones were used for the first time in Afghanistan, where the U.S. military deployed a Predator UAV armed with Hellfire anti-tank missiles.

But the biggest coup came in November 2002, when the Central Intelligence Agency used a Predator to blow up a car carrying six suspected al Qaeda operatives in Yemen, including one man suspected of involvement in the bombing of the USS Cole in 2000.

``Everyone saw their use in operation Enduring Freedom and Iraqi Freedom, so there's growing confidence in the systems,'' says George Guerra, deputy program manager for the Global Hawk at Northrop Grumman. ``What we are able to do is remarkable.''

Advances in technology attracted defense contractors and scientists to the UAV workshop.

Visions of huge profits are keeping them there: Rumsfeld's mandate for a fully connected, wired battlefield has directed billions of dollars into remote vehicle development.