The US Air Force’s potential shift to adaptable ‘light fighters’ to solve budget woes is more complicated than it seems

But while the F-16 delivered important technological breakthroughs, its real claim to fame was the ability to fight well above its weight class for a serious bargain — ringing it at just more than half the price of the heavy F-15 per jet. This allowed the US Air Force to embrace what’s commonly known as a “high/low mix” of fighters — an approach that’s transitioned over the years to see both the F-15 and F-16 as “low” end fighters, with the F-22 and F-35 assuming the “high” end role.

Allvin argued that America’s existing approach to fighter design, which sees lengthy developmental timelines followed by high-cost procurements and even higher-cost sustainment, is predicated on the “underlying assumption” that the fighters will stay technologically relevant for long enough to substantiate the mountains of funding dollars the programs burn through.

But with a long list of foreign nations now fielding stealth fighters of their own and emerging technologies like artificial intelligence promising to make air defense systems more capable than ever, Allvin believes that “underlying assumption” no longer holds true.

“That proposition can become an albatross. It’s still functioning, but it’s not as effective,” Allvin said of these high-end fighters as their lifespans wear on.

The “light fighter” concept and the digital century series

In other words, the original Century Series of fighters aimed to make rapid technological progress through the use of somewhat modular avionics systems and other onboard equipment that could be reused in subsequent aircraft designs rather than needing to devise entirely new hardware for each. Roper’s more modern “Digital Century Series” would take that concept to the next level, using digital engineering and virtual testing environments to rapidly mature fighter designs and subsystems toward service in modern modular fighters.

General Allvin also provided vocal support for Roper’s pitch at the time, saying, “‘Built to last’ is a tremendous 20th-century bumper sticker, and the assumption then was, whatever you had was relevant as long as it lasts. I’m not sure that’s true anymore.”

In 2021, a similar concept was also discussed by then-Air Force Chief of Staff (and current Chairman of the Joint Chiefs of Staff) General Charles “CQ” Brown, who suggested the branch shift toward fielding what many called a “5th generation minus” fighter design that would leverage modular systems based on those developed for the F-22 and F-35 in lower-cost aircraft with shorter service lives.

This would allow for rapid advancements in aircraft design and performance, as each new fighter iteration would be similar to the last, with a series of improvements cultivated through experience with the previous design. Pilots and maintainers transitioning from one aircraft to the next would face minimal training challenges, as the majority of the systems and aircraft functionality would remain the same.

Rather than fielding a new clean-sheet fighter design every 10 years, the majority of the previous fighter airframe and systems would be retained from one iteration to the next, swapping out only the design elements or internal components that need to be upgraded or changed to suit the shifting needs of the modern battlefield.

One iteration might come with a different wing or tail design meant to improve stealth, range, or loiter time, while the cockpit, avionics, and other onboard equipment could remain unchanged. Modular avionics systems could simply be swapped out of existing jets or replaced in the next iteration, resulting in a rotating fleet of fighters that are overwhelmingly similar to one another for the sake of training and maintenance but that continuously field new technologies or design methodologies meant to offset advancements in adversary defenses.

Breathing new life into the fighter industry

Today, the vast majority of a fighter’s overall program cost is associated with long-tail sustainment — meaning the cost of operating, maintaining, repairing, and upgrading aircraft over their intended lifespans.

The F-35 program, for instance, is often referred to as a $2 trillion effort as though that immense figure represents the high research, development, and procurement costs of these jets when, in reality, $1.6 trillion of that figure — a whopping 80% of the total cost — comes from the projected maintenance and sustainment required to keep the stealth fighter viable throughout its intended lifespan, which stretches all the way into the 2080s.

To dramatically oversimplify the math, that shakes out to about $2 trillion for a fleet of roughly 2,500 fighters operated over the span of 65 or so years — or roughly $800 million invested into each airframe for six and a half decades of service, with around $640 million dedicated to sustainment and only around $160 million in research, development, and procurement costs per jet.

The biggest problem with shifting to the Light Fighter or Digital Century Series acquisition model for the US Air Force is that it’s simply never been attempted in the modern era, and as such, there are few places to look for reliable data when attempting to assess the most effective path forward. Either decision will quickly become the fulcrum point of a new cost lever that stretches all the way to the end of the 21st century, and as such, a seemingly small miscalculation on today’s end could very quickly become an insurmountable budgetary shortfall a few decades down the road.

Air Force acquisitions are an industrial and economic behemoth, and as is the case with any massive enterprise, making such a dramatic pivot would require overcoming a great deal of cultural inertia both within the branch and, even more likely, within America’s industrial base. For companies like Lockheed Martin, winning a fighter contract that includes long-term sustainment is effectively a guarantee of massive revenue numbers for a half-century or more, and that’s something these influential corporate giants would likely fight to keep on Capitol Hill.

That isn’t to say these aren’t challenges that can be overcome — airpower has always been an evolving enterprise, after all — but with so many question marks looming overhead and the near certainty that such a shift would face some serious political challenges, one could make a reasonable argument that it’s simply too late to try to force this change onto the fighters already in development today.

Getting these new jets into service under an all-new acquisition model within strategically necessary timelines would require immediately implementing these sweeping changes across the branch, the industry base, the designs themselves, and the Air Force training doctrine all at once — all while the Air Force splits its budget and focus among other high-profile endeavors already underway like the B-21 Raider and LGM-35A Sentinel ICBM.

And to be clear, that’s not just the assessment of a cynical researcher looking for holes to poke in an exciting new concept — it’s actually the position argued by Air Force Secretary Frank Kendall just last year.

Last year, it seemed as though Kendall had nixed the idea of pursuing this concept for at least the time being, but since then, the Air Force’s economic outlook for the years ahead has certainly changed — so much so that the Next Generation Air Dominance fighter program that was expected to deliver a production contract this year is now being re-evaluated.

As too-important-to-fail programs like the LGM-35A Sentinel ICBM swell to 81 percent over budget, the Air Force has to adjust to accommodate the loss of tens of billions of dollars in near-future planning, and with contracts already awarded for these new missiles and new stealth bombers in the B-21 Raider, the only big-ticket item left on the chopping block is America’s next air superiority fighter.

Multiple different options are now being considered to ensure America can maintain air dominance in the decades ahead, but for significantly less than initially anticipated. This includes stretching the service lives of F-22 Raptors, which are already amid a multibillion-dollar update meant to ensure they overmatch the most advanced adversary jets entering service.

The F-22 design may date back to the late 1980s, but the aircraft still has the stealth and aerobatic chops to maintain a competitive advantage for years to come, but with Raptor production cut short after just 186 airframes were delivered — only 150 of which were actually combat coded — the Air Force is facing the risk of airframes aging out of service before a viable replacement can be fielded.

The LGM-30G Minuteman III ICBMs America operates as its land-based nuclear deterrent today started entering service all the way back in 1970 with a projected 10-year service life, meaning they were slated to be replaced by newer and more modern weapons starting in 1980. Its intended replacement, eventually known as the LGM-118A Peacekeeper, didn’t make its first test flight until 1983, with the first 10 weapons reaching service in 1986.

However, the shifting geopolitical landscape following the fall of the Soviet Union in 1991 and the subsequent Strategic Arms Reduction Treaty (START) II signed in 1993 saw only 50 Peacekeepers ever built — all of which were subsequently retired by 2005. As a result, the United States has spent billions trying to keep its aging Minuteman IIIs viable decades after their intended lifespans and now has acknowledged that they’ve reached the point where it’s no longer feasible to keep them in service.

As a result, the Air Force now has no choice but to swallow the ballooning cost of this program, which has nearly doubled in budget over the past few years, simply because the missiles that were initially meant to serve for roughly 10 years will now be on duty beyond their 60th birthday.

The Air Force would almost invariably find itself having to argue to justify the purchase of a new slew of fighters in the 2040s, as lawmakers question whether the jets designed to last for only one decade really need to be replaced after all, with many arguing that swapping out modular systems should be sufficient to maintain its competitive edge. Then, the debate would begin anew in the 2050s, the 2060s, and so on, with the concept’s efficacy teetering in the balance every time.

Unlike the Minuteman III, which was originally slated for just a 10-year service life, the LGM-35A Sentinel is expected to stay in service for better than a half-century because the Air Force has no intention of making the same mistake twice with these long-range munitions. It’s well aware of the fact that fielding ICBMs that would need replacements 10 years down the road assumes funding for those replacements will be forthcoming, and in today’s political climate, that’s an awfully big assumption.

And yet, because of the Sentinel’s immense cost overruns, the NGAD program now runs the risk of becoming the fighter equivalent of the Minuteman III itself — a system meant to serve for 10 years but dragged down the road for decades as officials and lawmakers try to dodge the sticker-shock of fielding a replacement until they have no other options left.

And then, when that program goes 81% over budget before the first aircraft is even delivered the way Sentinel has, Defense officials would be forced to echo the same talking points about how the strategic need for replacement outweighs the economic impact of cost overruns.

Cultural inertia in the fighter business

The use of modular systems and open system software architecture would allow for a great deal of commonality between airframes, reducing the costs associated with standing up two separate fighter production lines. Nonetheless, for a cash-strapped Air Force, this would be a significant challenge.

And, of course, with the F-35 still in active production, the arithmetic gets even more complicated.

Some might reasonably argue that the F-35 itself, which now rings in at an average of $82.5 million per runway variant — roughly $7.5 million less than a new F-15EX — is already positioned to fill that “low” end role as compared to the NGAD’s anticipated flyaway costs of some $300 million per airframe. After all, $82.5 million may sound like a lot, but it’s significantly lower than the adjusted prices on some of the previous era’s top-tier platforms like the F-14 Tomcat, which, when adjusted to today’s inflation, cost nearly $121 million per unit in the 1970s.

But then, in my lifetime, we’ve seen things like stealth go from a handful of boutique, specialized, and classified airframes that operated in secret and only under cover of darkness to the F-35 becoming one of the most widely operated fighters on the planet, with more than 1,000 airframes delivered and production expected to continue well into the 2040s to meet demand. There is simply no denying that things are changing — and changing quickly.

So, maybe I’m just being a part of that cultural inertia that such a momentous plan would need to overcome in order to succeed.

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