NATIONAL HARBOR, Md. — Remotely piloted aircraft must undergo major changes to stay relevant in a future battle space, a panel of experts said Tuesday.

"As we go forward, the question is. 'How do I employ this unmanned component in a non-permissive environment?' " said Kenneth Callicutt, the director of capability and resource integration for US Strategic Command.

In their now near-ubiquitous role in operations against terrorism worldwide, RPAs have operated almost exclusively in a permissive environment without many direct threats.

That's something that's changing as US adversaries — and especially near-peer competitors — adjust to the Air Force's increasing reliance on the unmanned systems, the group of experts said at the annual Air Force Association Air Space Cyber conference here.

"When you use something a lot, the folks that you're using it against adapt to it," said James Gear, the vice president for advanced systems at L3 Communications. "The enemy gets a vote. You can never be satisfied with the status quo."

Changes could be incredibly wide-ranging, including building RPAs with stealth elements, or cheaper expendable systems that would lessen Air Force worries about survivability, the panel said.

But Callicutt argued that communication systems must also improve, and that operators need to be prepared for enemies attempting to jam signals between RPA controllers and the aircraft themselves.

"What are we doing to plan around not having [satellite communications]?" he said. "When they're disconnected, what is that vehicle going to do?"

RPAs might require a degree of complete autonomy in the event they lose contact with human controllers, the panel said. That could include something as relatively simple as programming an RPA to return to predetermined coordinates if communications are jammed.

The fact that RPAs are remotely piloted and usually cheaper than manned aircraft means the Air Force "can afford risk" to experiment with new systems, Callicutt said.

Testing out new technology or new ways to operate could happen at a much more rapid pace, he said, because the Air Force wouldn't initially need to be as concerned about safety. If a cheap unmanned system crashes on a testing range, it doesn't put any pilot's life at risk.

Tom Clancy, the vice president of unmanned aerial systems for Aurora Flight Sciences Corporation, said he would like to see RPAs start to achieve true autonomy and not require human interaction for some operations, which he dubbed "more robots doing the work of less people."

"Right now we have a situation where our unmanned systems take more people to operate then our manned systems," he said. "I think we definitely have the effectiveness. Check. But I think as we look at going forward, we want to see how can we deliver on the lower cost in terms of basically more capability with less people."

That could include true drones that would fly out, survey a battlefield, and relay the information back to mission planners without much human interaction, Clancy said.