In a departure from the dual-service F-35 effort, the Pentagon's sixth-generation fighter likely won't be common between the Air Force and the Navy, a top Air Force general said Friday.

The next generation of fighters will likely be designed as separate aircraft across the services because the Air Force and Navy will have unique mission requirements in future decades, said Lt. Gen. James "Mike" Holmes, deputy chief of staff for plans and requirements.

"We'll have some different requirements for what we need based on the different things we are expected to provide for the joint force," Holmes said Friday during a media roundtable at the Pentagon. "It's not likely [it will be a common airplane]. We'll use common technologies and maybe some common things, but at this point we think it will be a different enough mission that it won't be the same airplane."

It's a departure from the fifth-generation F-35 Lightning II which will be used by the Air Force, Navy, and Marine Corps. The F-35 was designed as a joint-service fighter, with three different variants built for the various services.

But it looks like the sixth gen fighter development will more closely resemble current aircraft, where the Air Force operates the F-15 and F-16, and the Navy flies the F-18.

Last year, the Navy and Air Force said they were set to begin a joint analysis of alternatives, or AOA, to explore solutions to ensure air superiority into the 2030s and beyond. While the Navy went ahead with its AOA, the Air Force decided to delay its own effort, Holmes said. Still, the two services are collaborating closely on the project, he stressed.

"We took a year out on purpose to try to bring in a broader picture," Holmes said.

Instead of moving forward with the AOA, the Air Force stood up a Capability Collaboration Team (CCT) to study the possibilities for a sixth-generation fighter. The Air Force worked with industry, the other services, academia, scientists, and government research centers to narrow the options down to two possible development paths, Holmes said. The team will brief Air Force leadership on its findings in the spring, he said.

"We're a multi-domain Air Force, we're going to approach problems with multi-domain solutions," Holmes said. "We wanted to open the aperture and take a look at what space, cyber and air capabilities can come to bear to try to regain that capability advantage we had in air-to-air against our potential threats."

The Air Force has included money in various funding streams within its fiscal year 2017 budget request for experimentation and technology demonstration in order to minimize risk for the sixth-generation fighter in the long term, Holmes said. The service's funding profile for next-generation air dominance – which is not limited to sixth gen -- includes $20.6 million in FY17, and about $13 million each in FY18 and FY19 for research and development, according to official budget documents. The Air Force also included $75 million in FY17 FY19 for "innovation and experimentation," which could be used for sixth-gen fighters, according to a service spokeswoman.

The Air Force will decide this year exactly how to spend that cash, Holmes said.

Lara Seligman is the air warfare reporter for Defense News. She can be reached at lseligman@defensenews.com and you can follow her on Twitter at @laraseligman.

Phillip Swarts is the aircraft and space operations reporter for Air Force Times. He can be reached at pswarts@airforcetimes.com and you can follow him on Twitter at @PFSwarts.