The once mighty United States Air Force has settled into a rhythm of buying just 48 F-35As a year. To the layman, that may sound like a lot. It’s not. That’s down from its 2015 plan to acquire 80 a year, which fell to 60 a year in 2017 and just 41 in Fiscal Year 2022.

There are many reasons why the Service should be buying more F-35s, but for the sake of time, let’s narrow the list to the six most pressing.

1. The West’s lead in technology is rapidly fading. US stealth fighter technology has dominated the world since the late 1970s, but whatever paradigm existed prior to 2017 began to change with China’s fielding of its stealthy J-20. They have since acquired upwards of 250 J-20s and their production rate will reportedly begin delivering 100 of these stealth fighters a year by the end of 2023.

China acquired the lion’s share of their stealth technology by breaching through classified DoD and contractor firewalls to steal F-35 material design information. While troubling, the fact that China did not develop that technology still led many to believe whatever technology China ultimately fielded would be similar but inferior to that of the Lightning II.

Unfortunately, anecdotal stories of stealth-v-stealth encounters over the Pacific have brought that assumption into question and it is very likely that the J-20’s stealth is much better than many pundits expected. Assuming that is true, it dismantles previous thoughts of fourth- and fifth-generation US fighters “teaming” together in a fight with China. The fourth-generation jets just will not survive in a modern-day air-to-air environment.

2. If the war over Ukraine has taught us anything, it is that fourth-generation fighters cannot survive in a modern surface-to-air missile (SAM) environment. Fourth-generation jets, and more advanced fourth-plus-generation models, are those designed and built from the late 1970s through today’s F-15EX. Lacking stealth, they are completely outmatched in a medium to high-threat environment like the one over Ukraine.

The Ukrainian countryside is strewn with the remains of Russian four-plus-generation Su-35s, which have been downed by Ukrainian manned S-300 surface to air missile (SAM) system, which was designed in the late 1960s and began fielding in the mid-1970s. Those jets would stand no chance against the much more advanced S-400, which the Russians are using against the Ukrainians. Without air dominance over the battlefield, both armies have been relegated to costly trench warfare. Yet the Air Force continues to buy the four-plus-generation F-15EX, which costs more than the much more capable F-35A.

3. The F-35A is markedly less expensive to acquire than the F-15EX, and it can operate in and around the most advanced SAM systems in the world.

In 2017, Boeing boasted about the F-15EX costing the same as the $80 million F-35A, but they were omitting significant component costs with that claim. It turns out that the price quoted by Boeing and within Air Force budget documents was incomplete at best, and intentionally misleading at worst.

Aside from the number of occupants in each jet, the real difference between the single-seat F-15C and the two-seat F-15E(X) is the latter’s conformal fuel tanks. Those tanks significantly increase the range and weapons carriage capacity of the basic F-15 platform, but cost $5.3 million per jet. Like the language surrounding the EX’s expensive electronic countermeasures system, the Air Force financial management documents led Congress to believe the tanks were included, but the tanks were somehow omitted from the cost data.

Not until the unfunded priorities list for Fiscal Year 2024 revealed the need to purchase those conformal tanks, did it become clear that both Boeing and the Air Force were masking the real costs of this platform. That ruse continued from 2017 through last Spring, when the Air Force was committed to buying at least four squadrons of these jets. Only after the Service went all in on acquiring the fourth-generation F-15EX did it find more details on the actual cost of the EX weapons system, which now exceeds the cost of the F-35A by 20 percent.

4. Congress was misled on sustainment costs – the F-35A is also significantly less expensive to fly/sustain than the F-15EX.

In 2017, DoD’s Cost Assessment and Program Evaluation (CAPE) lambasted the notion that the F-35A would cost less to operate than the F-15EX. But even then, CAPE’s own internal, unclassified (but closely-held) documents showed the operational costs of the well-established F-15E, stated in terms of cost-per-tail-per-year, were more expensive than the F-35A.

The F-15E is the elder sibling of the F-15EX and, while the “E’s” operational costs should be representative of the EX, once that weapons system settles into a mature rhythm. On the other hand, the 2017 F-35A’s figures were from the jet’s first years of the jet’s – notoriously the most expensive of a weapons system’s operational life.

Even so, the F-35 was still cheaper to fly than the F-15E(X). As the F-35A matured over the next two years (2020) in the same CAPE graphic, its cost-per-tail-per-year fell to the point where the F-15E was 10 percent more expensive to sustain than the F-35A.

5. Air Force readiness and capacity levels are at all-time lows. At the height of the last Cold War, the Soviet Union’s inventory of fighter and bomber aircraft significantly exceeded NATO’s. The West offset those numbers by fielding as much brand-new fighter technology as they could afford, while increasing fighter pilot readiness. US fighter pilots were logging 200-300 hours a year in brand new F-15s, F-16s, and A-10s, while Soviet pilots were flying mostly dated Sukhoi (Su) and Mikoyan (Mig) aircraft, logging fewer than 130 hours a year.

Today, US fighter pilots are the ones getting fewer than 130 hours a year, while flying the oldest and smallest fighter fleet in US Air Force history. Chinese fighter pilots, on the other hand, are getting more than 200 hours a year in much newer fighter aircraft. With a limited number of mission-capable aircraft, and readiness levels on a par with Soviet pilots in the late 1980s, the Air Force needs to be fielding as many viable fighters as it can.

6. Knowing the realities associated with each of the five previous points, the Air Force has tried multiple times to cancel the acquisition of the F-15EX as the math behind paying more for less just doesn’t add up.

With a flyaway cost of $92.4 million, the F-35A is a complete weapons system that comes with internal targeting and Infrared Search and Track (IRST) systems and is capable of operating in the highest threat environments in the world. The newly revised flyaway cost for the F15EX of $97.9 million still does not include the targeting or the IRST pods the jet needs to operational, but even then it will be limited to low to medium-threat environments like the one over Syria. When you add the price of those pods, the “known” costs of each F-15EX increase to $111.0 million. The Air Force would actually save $13.1 million dollars for every F-35A it opted to buy instead of the F-15EX. Saving thirteen point one million dollars to get a much more capable jet seems like an easy decision.

Every other nation that has compared the cost and capabilities of the F-35A against even less expensive fourth-generation platforms has come to the same conclusion. And yet every time our Air Force has removed the more expensive, less capable F-15EX from its budget projections, the EX has magically reappeared in the President’s budget, with OSD offsetting the F-15EX purchase with cuts to the F-35 program.

With China’s growing stealth capability and capacity, and its willingness to invest heavily in readiness, we can no longer afford to buy anything but the best. There is no doubt that the F-35 is the most dominant fighter in the world. Our nation needs to acquire as many of these jets as quickly as it can.

About the Author 

John Venable is a Senior Research Fellow for Defense Policy in the Center for National Defense at The Heritage Foundation. He is a graduate of the U.S. Air Force Fighter Weapons Instructor Course and a veteran of three combat operations, with more than 3,300 hours in the F-16C.