Uncertainty, challenges mark future for military's unpiloted aircraft.

• Author: Beidel, Eric

Air commanders often quote five-star Army, and later, Air Force Gen. Henry H. "Hap" Arnold, who on V-J Day 1945 proclaimed that "the next war may be fought by airplanes with no men in them at all."

More than 65 years and dozens of conflicts later, the general's prophecy hasn't come true and some military leaders doubt it ever will.

Unmanned aerial systems have enjoyed a coming-out party in war zones. Their use in Iraq and Afghanistan has shown that they are invaluable in uncontested airspace. But questions remain about how the current generation of U.S. drones would fair in unfriendly skies.

At a recent industry conference, Air Force Lt. Col. Steven Tanner made a gun with his fingers and impersonated the sound of planes being shot down.

"If we went to a North Korea scenario right now and put a bunch of Predators and Reapers in the air, you better bring the replacements because they'd be falling out of the sky," said Tanner, doctrine division chief of the Joint UAS Center of Excellence at Nellis Air Force Base, Nev.

"The UAS honeymoon is over," he said.

The Pentagon this year bought more unmanned aircraft than manned and expects to spend more than $24 billion from now through 2015 to build and buy pilotless planes. But many leaders across the services believe that several myths need to be exposed to determine the most realistic future for the systems.

The military's unmanned aircraft range in size from handheld vehicles no bigger than a child's toy to the Air Force's Global Hawk, which has the wingspan of a 737 commercial jet. Though they have been used to launch attacks, drones mostly are employed as spy tools that gather intelligence and provide situational awareness to troops on the ground.

"It does not meet my definition of a weapons system," said Air Force Gen. Roger A. Brady, who at a conference in July all but dared a crowd of UAS enthusiasts to prove him wrong. "If I see an F-16, that's a weapons system. You know where it is, you know where all the electrons are going, you know what's happening, you know who's responsible. There's a program manager that you can call and yell at. There are operators. There's a command chain."

It doesn't work that way for a UAS, said the commander of U.S. Air Forces in Europe. A signal from an aircraft is sent to a satellite, "then a million miracles happen along optical links and it ends up in Las Vegas. I'm not even confident we've mapped that whole thing. And by the way, it goes through commercial...