by DAVE MAJUMDAR

America’s next jet fighter—a so-called “sixth-generation” warplane— could be fundamentally different than the current fifth-generation F-22 and F-35. But it’s not clear yet what exactly that means.

In fact, terms like “fighter” or “bomber” might be holding the Pentagon back from taking full advantage of new technology.

“The technology has taken us to a point that has exceeded the vocabulary and semantics that have described aircraft in the past,” says David Deptula, a retired U.S. Air Force intelligence chief and former F-15 pilot. “When you move to sixth-generation, it is going to be even more different than the significant changes and advances in the technology that has given us the capabilities resident in the F-22 and F-35.”

Although the F-22 remains the world’s best air-to-air fighter, it’s now more than 10 years old—the first operational examples having been delivered to the Air Force in 2003. Given the time it takes to develop a modern warplane, the Air Force must start thinking now about what comes next.

“[The F-22] will be the preeminent airplane in the world into the 2030s, until we come out with whatever the next platform or capability is,” Gen. Mike Hostage, then-chief of Air Combat Command, said at the Air Force Association conference in September 2013.

What technologies might be included in the new warplane is still an open question. “It’ll be some type of game-changing capability,” Hostage said. “It’s not going to be an iterative growth of this [current] capability.”

The Pentagon’s fringe-science Defense Advanced Research Projects Agency has already started working on that problem alongside the Air Force and Navy. The two services each have their own sixth-generation fighter studies underway—the “F-X” and “F/A-XX,” respectively.

The Navy project appears to be running somewhat ahead of the Air Force project because of the sailing branch’s need to replace its F/A-18E/Fs in the 2030s. In any event, for the next decade or so the Pentagon will build the F-35—the F-22’s newer, smaller and more compromised cousin—just to keep up numbers.

The F-35 buys the military time to plan for a successor, says Rebecca Gant, president of IRIS Independent Research and a paid consultant to the Air Force, Navy and aerospace industry. “The next five years should be devoted to maturing technologies: efficient, supersonic propulsion; on-board lasers; masterful electronic warfare; longer-range missiles; and other design and materials challenges, to include increasing stealth.”