WASHINGTON » In an acknowledgment that the military may be pricing itself out of business, the Air Force on Wednesday called for a shift away from big-ticket weapon systems that take decades to develop and a move toward high-technology armaments that can be quickly adapted to meet a range of emerging threats.

An Air Force strategic forecast, looking 20 years into the future and spurred in part by looming budget constraints, also calls for a faster pace, with lower price tags, in developing both airmen and the technology they use, warning that the current way of acquiring warplanes and weapons is too plodding.

The report, described as a "call to action" by Secretary Deborah Lee James of the Air Force, limits itself to how the country’s most tech-heavy military service can adapt to looming threats and budget constraints. But it is also a warning to and an admission from the entire Defense Department that with military compensation and retirement costs rising sharply, the country may soon be unable to afford the military it has without making significant changes to the way it does business.

"To boil this down, we have to buy things very differently and develop and employ our people differently," said Maj. Gen. David W. Allvin, one of the authors of the report. "We have to behave more like an innovative 21st-century company."

Between 1998 and 2014, annual compensation costs per active-duty service member increased by 76 percent, to $123,000, while the overall defense budget increased by 42 percent — yet, since 2010, the base Defense Department budget, not including spending on the wars in Iraq and Afghanistan, has been declining, according to the Center for Strategic and Budgetary Assessments. So far, the military has dealt with the sharp increase in personnel costs by cutting the number of service members, and has managed to keep expensive weapons acquisition and technology at the same percentage of the overall budget — around 30 percent — as personnel and maintenance and training.

But with the Army, the largest branch in the military, now headed to its lowest personnel numbers since before the World War II buildup, Defense Department officials, particularly in the Army, warn that more cuts could bring increased risks to deployed service members. While the Air Force and Navy, with historic reliance on technology, are widely viewed as more willing to make personnel cuts than their Marine and Army counterparts, even officials in those services say there is a limit to how much more they are willing to reduce personnel.

But a potential gap between good intentions and spending reality remains, and it is unclear how serious the Air Force is about its call to move away from its focus on big, expensive weaponry, in particular advanced fighters and bombers. After all, the report is a long-range forecast that looks to change the culture of weapons development two decades or more down the road, so expensive weapons already in the pipeline remain relatively safe.

Over past decades, similar talk of streamlining the military has crashed into opposition from members of Congress, defense contractors and the military itself, which often work to protect bases, weapons systems and other budget pets. And calls for saving money by adopting new technologies are not new; Donald H. Rumsfeld, a former defense secretary, announced a goal of imposing "transformation" on the military to create a smaller, lighter, more agile — and cheaper — force, but his ideas were forced aside by the terrorist attacks of Sept. 11, 2001, and the wars in Afghanistan and Iraq.

For example, nowhere in the report is there mention of scaling back on the trouble-plagued F-35 jet fighter — in development for 14 years so far — which was temporarily grounded last month after another in a series of problems. Nor is there talk of getting rid the next generation long-range bomber, which the Air Force is working on for around $550 million per plane and which is expected to debut somewhere around the mid-2020s.

"They’re still going to buy the Joint Strike Fighter," said Todd Harrison, a senior fellow at the Center for Strategic and Budgetary Assessments, referring to the F-35 warplane. "They’re getting squeezed, but they’re still going to buy the next generation bomber and the KC-46 tanker" for aerial refueling.

In fact, introducing the report on Wednesday, both James and Gen. Mark A. Welsh III, the service’s chief of staff, made a point of saying that the F-35, the next-generation long-range bomber and the KC-46 refueling tanker are all high-priority items for purchase. Welsh offered a vigorous defense of the F-35, the world’s most expensive weapons project, and called the recent failure of an F-35 engine at a Florida air base a fixable problem.

"The F-35 is the answer, the only answer, that ensures that future fights won’t be fair fights," he said. "I’m confident that the program will remain on track."

Officials said Air Force weapons systems that could be targeted in the new shift — the Air Force is calling it "strategic agility" — is the next-generation replacement for the Joint Surveillance Target Attack Radar System, or J-STARS, a surveillance airplane that provides information on ground forces to commanders in the air and on the ground, as well as the replacement training aircraft — called TX — used to train pilots.

Space and information programs could also see their spending cut in this new approach, military analysts said, with a view to building them in a more piecemeal way that would allow for quick adaptation as new technology emerges.

"The notion is, we can’t afford the big bang programs anymore, so what if we approached it differently, looking at adding capability in smaller chunks?" said Beth McGrath, a director at Deloitte Consulting and former deputy chief management officer for the Defense Department. "We say, ‘This is the big thing we want,’ and then we go buy the big thing. But there’s a better way to do this."

Air Force officials said they also believed they could incorporate this new system into some existing programs — the service has been retrofitting its aging B-52 bomber fleet for decades to meet changing needs. A senior Air Force official said Wednesday that engineers were looking into whether they could integrate some of the newest advances in aircraft engines, including the latest in propulsion technology for fuel savings, and put them into existing systems, instead of simply starting from scratch all over again with new planes.

Allvin, who worked on the report, said in an interview that the service also must look for how to make airmen more adaptable to newtechnology, and seek ways to harness advances underway at U.S. high-tech giants like Google. He suggested that the Air Force might restructure pension and retirement programs so airmen could still qualify for military retirement benefits even if they spend their careers switching back and forth between the service and high-tech firms in the private sector.

"What if you entered the Air Force knowing you could serve for a few years, then go to work for an innovative tech company, and then return to the Air Force?" he said. "We could enter into partnerships with cutting-edge companies and allow our work force the opportunity of a more flexible retirement system that allows you to do two different jobs and still get to a 20-year retirement. It might take 35 years, but you would get here."

After two costly and exhausting land wars and the fiscal reality of government austerity, the Air Force report could signal similar shifts by the entire military.

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