Unmanned airplanes have almost become another branch of the military, dropping bombs, spying on terrorist camps and even threatening enemy aircraft in Iraq and Afghanistan.
Now government and aviation experts are planning to make room for more robot aircraft over domestic skies: working as airborne traffic cops, patrolling the border and maybe even shuttling cargo between cities.
It's not a sci-fi fantasy. In fact, the Federal Aviation Administration is now studying how to safely fit these unmanned aircraft into the nation's busy commercial airspace.
"The success in the military has started to bleed over to the civilian environment," said Wesley Randall, a former Air Force logistics officer and professor at Auburn University's department of supply chain management. "People are saying this isn't a niche, gee-whiz technology. These are things you need to think about."
The FAA granted Randall and his colleagues at Auburn a $300,000 grant last week to do safety-related analyses of unmanned aerial systems. The government currently permits some law enforcement agencies to fly remote-control aircraft with a waiver from federal rules.
But the numbers of unmanned vehicles -- and their uses -- are growing. That means a greater chance of something going wrong.
Randall and his team will consider how and where robot craft should fly -- which altitude, which routes and at what times.
There are bigger questions as well. Should these drones be part of the FAA's air traffic control system and get directions from control towers? Should remotely-operated pilots with joysticks have the same training as commercial pilots? Who's responsible if there's a crash?
Peter Singer is author of the new book "Wired For War" and is a senior fellow at the Brookings Institute in Washington, D.C. He says that unmanned aircraft are inching closer to prime-time, following a well-trodden march of technology from military to civilian uses.
"Nobody is saying that all humans will be replaced in war," Singer said. "But there are always evolving roles in war and civilian society. Next couple decades there will be some kind of pairing of humans and unmanned systems."
That synergy of man and machine is already happening in the military.
Northrop Grumman is building the world's first unmanned combat aircraft for the Navy. The $635 million X-47B takes its test flight from an aircraft carrier deck in December. Last year, Air Force officials awarded "aircraft wings" to 24 new cadets to pilot unmanned aerial systems.
Even though commercial pilots use automatic controls to fly and land modern jetliners, the human fear factor will likely prevent the idea of a passenger airline without a human at the helm. "Somebody could invent a remotely piloted airliner and nobody would fly it," Randall said.
But cargo planes might work. Randall notes that unmanned airplanes could carry cargo loads across unpopulated areas or the ocean. Without a crew compartment, these planes won't need to be pressurized for human occupants.
"They are inherently more green," Randall said. "They use less gas, have less weight and overall less waste."