That's the vision of Northrop Grumman Corp., which is working on an autonomous fighter programmed for aerial combat without human control. Northrop has already refueled its experimental X-47B unmanned combat jet in flight and made takeoffs and landings from an aircraft carrier.

"It's a very dynamic, moving 3-D environment," said Scott Winship, Northrop's vice president of advanced warfare development. "It's a difficult problem. But it's something that we're very keen to resolve."

As drone makers and users gathered this week in Atlanta to discuss topics such as package deliveries and airborne surveys of rail lines, U.S. defense contractors outlined the emergence of vastly more complex technology in pilotless aviation. While a dogfighting drone remains "a ways out," as Winship put it, the time frame for achieving that capability may be measured in years, not decades.