A soldier wary of what's over the next hill can snap together the nose, tail, body and two wings of the Evolution XTS, all six pounds of it, and find out. Just load a hand-held sling shot and let the airplane fly, for 90 minutes if needed. Guide it by computer and watch real-time video stream in.

BAI Aerosystems Inc. assembles the miniature planes for the military on its factory floor in Easton. In Manassas, Aurora Flight Sciences Corp. is developing a pilotless plane with a similar mission, only this one looks like a trash can with fins and takes off like a helicopter. And in Ellicott City, the fledgling Optemax LLC, only two years old, plans to create technology for the Navy that it says would allow shoulder-launched planes to transmit data equivalent to nine DVDs in one second.

After Sept. 11, 2001, "mini" drones have created big business for small Washington area companies, those that make them and those that load them with tiny cameras and sensors.

Since the terrorist attacks, unclassified spending on drones of all sizes has jumped nearly fivefold, from $364 million in fiscal 2001 to $1.67 billion in fiscal 2006, according to the Pentagon. And the number of drones rose from 100 to more than 2,000.

"It's practically become a retail business, because it's easy for a small company to come up with a small drone," said James Jay Carafano, a senior military affairs fellow at the Heritage Foundation. "So many of these companies have dual-use technologies that can be tailored for just about any kind of mission."

The biggest chunk of money goes to the huge drones, such as the Global Hawk and Predator, that were rushed into Afghanistan and Iraq, where they dazzled the military intelligence community. For more than 24 hours at a time, those drones hover at high altitudes, scoping out enemy activity.

But the mini drones are far more common, making up about 75 percent of the military's pilotless planes. They are cheaper to build, easier to use, and popular with the ground troops because they have saved hundreds of lives, said Steven Zaloga, a senior analyst with the Teal Group Corp., a defense consulting firm in Fairfax.

Aiding their proliferation is the Pentagon's decision to give millions of dollars to the commands overseas to spend on their most pressing wartime needs without going through the time-consuming purchasing bureaucracy, Zaloga said. Getting rid of the red tape opened the flood gates for small firms.

"These mini drones gave the people with their boots on the ground mini-intelligence systems, which in turn spurred more demand," Zaloga said. "Drones are no longer just for the general sitting in his Pentagon office."

BAI Aerosystems, a division of L-3 Communications Corp., is one of the companies taking advantage of that trend. The firm employs about 80 people in Easton who design and make planes that sell for as little as $5,000 each and can be carried in backpacks.

Since opening its doors in Rockville two decades ago, the company has counted the Army and Navy as its largest customers. But no single order has exceeded $3 million, said Jay Willmott, the company's executive vice president.

That is why the company was stunned when the Army began soliciting bids for a $125 million contract to build about 550 "backpackable" pilotless planes that weighed less than 25 pounds -- airplane, battery, and laptop to control and communicate with it included.

BAI got in the running with its Evolution XTS and survived the first round of cuts -- though defense giants Northrop Grumman Corp. and Lockheed Martin Corp. did not. But this month, it lost out on that contract to AeroVironment Inc. of Monrovia, Calif.

"We're not discouraged because we know these kinds of opportunities will come around again," Willmott said. "When you've got the likes of Lockheed and Northrop chasing a small [unmanned aircraft] program like this one, it's a bellwether for this market's potential."

As part of its contract, AeroVironment is supplying the Army with a four-pound, packable plane, called the Raven, that can be launched by throwing it like a football and can fly for about 90 minutes, usually less than 400 feet above ground.

Getting into the business, for many small firms, meant latching on to a prime contractor involved in one of the larger drone projects.

Aurora Flight Sciences took that path. When funds dried up for the global climate research planes it was building for NASA, the firm picked up subcontracting work in 1995 from Teledyne Ryan. Northrop Grumman acquired Teledyne four years later and ultimately produced the Global Hawk, the large, high-altitude drone used in Afghanistan and Iraq.

Today, Aurora builds about one-third of the exterior of each Global Hawk. But the firm hopes to branch into mini drones because it makes business sense, said John S. Langford, Aurora's founder and president. To that end it's building the GoldenEye-50, the garbage can-like plane with its propeller blades buried inside to increase safety and cut down on noise.

With the GoldenEye-50, Aurora can play a prime contracting role and produce drones in volume, creating efficiencies of scale. Let the big guys make the big drones and engineer the combat force of the future, Langford said.

"When you look at little airplanes, it's like building telephone handsets for the Bell system 75 years ago," Langford said. "We want to make telephone handsets for the Bell system. We're not trying to develop the Bell system."

Shirley Collier, chief executive of Optemax, wasn't even trying to do business with the military when she licensed what she considered promising technology from the Johns Hopkins Applied Physics Laboratory. But when Collier shopped the technology around to the commercial sector, none of the for-profit firms wanted to take a chance on a newcomer. So she applied for the Navy contract that calls for technology that can transmit vast amounts of data for pilotless planes. Now, her three-person operation in Ellicott City subcontracts most of the work to a team of eight PhDs, she said.

"The military had an immediate need, and we knew we could address it," Collier said.

The money at stake on drones of all sizes is not much by Defense Department standards. The $1.67 billion in unclassified funding set aside for drones is less than 1 percent of the entire defense budget, said Loren B. Thompson, an analyst with the Lexington Institute, a think tank in Arlington.

But the growth of the drone market makes it appealing, especially when the Bush administration has signaled its reluctance to spend more money on Cold-War-era weapons, such as fighters and destroyers, Thompson said.

"The administration is looking for cheaper weapons suitable for the unconventional enemies we're facing today," he said. "So the companies are looking around and saying: 'If the budget is not growing, then what particular activity might have some growth in it?' An obvious answer is unmanned aircraft."

Unmanned aerial vehicles, or UAVs, date back to the 1940s, when the Air Force and Navy used them to test radiation levels after nuclear blasts. But they were not used extensively for reconnaissance during combat until the end of the Vietnam War and then again at the start of Operation Desert Storm in the Persian Gulf in 1991.

That's when AAI Corp. of Hunt Valley joined with an Israeli firm to manufacture the Pioneer, widely considered the first successful new generation of U.S. drones capable of real-time intelligence gathering, Zaloga said.

The Pioneer was so effective that its sound began to intimidate Iraqis, said Steven E. Reid, vice president of AAI's unmanned air vehicle systems. "The Iraqis came to learn that when they heard the buzz of a Pioneer overhead, all heck would break loose shortly thereafter because these 16-inch rounds would start landing all around them," from a U.S. battleship about 60 miles away, Reid said.

More than a decade later, the Navy is using the Pioneer in Iraq and the Army is using AAI's Shadow 200, a 327-pound drone.

Now AAI hopes to break into the mini drone market as well. The company teamed up with Honeywell Aerospace more than a year ago to produce the Micro Air Vehicle, a small drone being tested by the Army that takes off vertically and flies for 90 minutes.

"If our customer is embracing the smaller UAVs, we want to be there for them," Reid said.

Interest in drones extends to customers who want to detect forest fires, patrol the borders, monitor traffic, and take part in search and rescue missions. Japan and Korea have used UAVs to spray crops.

The challenge in crossing over to the civilian side is determining how UAVs can safely share crowded air space with commercial airplanes and helicopters.

"But the commercial side one of these days will overwhelm and dwarf the defense side of it," said Daryl Davidson of the Association for Unmanned Vehicle Systems International in Arlington.

Whatever drives the market, it has become clear that a lot of companies want to come along for the ride. Consider AUVSI's annual industry gathering, Davidson said. This summer in Baltimore, about 3,700 people showed up, more than triple the turnout of five years ago.

Technician Jeff Thornton performs a routine inspection on an Aurora Flight Sciences Corp. GoldenEye-50, an unmanned flight vehicle, in Manassas.

The BAI Aerosystems Inc.'s pilotless drone, built in Easton, and its ground control station during a test.

Army Spc. William Pasiechnik launches a Raven, built by AeroVironment Inc., to conduct reconnaissance in Samarra, Iraq, in November 2004.