How the F-15 and F-22 should inform the F-47’s procurement

Shown is a graphical artist rendering of the Next Generation Air Dominance (NGAD) Platform, dubbed the F-47. (U.S. Air Force graphic)

The US Air Force needs to make some hard choices about its fighter aircraft to avoid ceding air superiority to China. Two new stealth aircraft have appeared in Chinese skies, and rising J-20 production rates mean China could have up to 1,000 5th-generation fighters by 2030 .

The Air Force’s F-47 promises to help offset some of these Chinese gains, but it can only do that if Pentagon planners make an informed decision on how much to spend on the new fighter, how many to buy and when to buy them.

The history of the F-15 and F-22 illustrates some of the choices lying ahead for the Air Force as it pursues the F-47 and reveals that, although the Air Force should consider buying more of the new fighters, a rush to acquire them could come at the expense of the service’s other procurement priorities.

The Air Force is still figuring out how to approach the cost and procurement schedule of the F-47. Cost estimates range from less than $100 million to as much as $300 million per aircraft. Other than naming 2028 as the goal for a debut flight , the procurement schedule for the F-47 is hardly discussed at all.

It is unknown exactly how many F-47s the US is seeking to buy. In 2023, then-Air Force Secretary Frank Kendall indicated the service plans to buy around 200 of what was then known as NGAD, but that was before the Trump administration’s program award to Boeing for the jet, as well as several years of real-world knowledge that could potentially change that figure. Still, for the sake of argument, we’ll use 200 as a baseline assumption.

Past spending on F-15 and F-22 can help shed light on questions surrounding F-47 costs. From 1973 to 1991, the Air Force purchased more than 1,000 F-15s at an inflation-adjusted average unit cost of almost $84 million in fiscal 2027 dollars. Funding for the F-15 took up an average of around 32% of the Air Force’s aircraft procurement budget during this time. From 1999 to 2009, the Air Force bought fewer than 200 F-22s with an average price tag of $291 million each in FY27 dollars. This accounted for 27% of the Air Force’s aircraft procurement budget. Regardless of whether the cost of a single F-47 falls closer to high- or low-end estimates, historical data show that the Air Force should expect the fighter program to account for roughly 30% of its annual aircraft procurement budget.

Today’s threat perceptions and strategic priorities vis-à-vis China much more closely reflect those of the Cold War than the Global War on Terror. Thus, the Air Force should aim to purchase more F-47s than it did F-22s. Advancements in stealth, networking and munitions since the Cold War means the Air Force does not need to buy over 1,000 F-47s, either. Recent analysis recommends buying at least 300 F-47s to meet the operational requirements necessary to counter China. Irrespective of specifics, the Air Force should treat 200 F-47s as a floor, not a ceiling.

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The F-15 and F-22 also give the Air Force two different acquisition schedules to apply to the F-47: “go fast” or “go steady.” The first five years of F-15 procurement consumed an average of more than half of the Air Force’s aircraft procurement budget during that time. In contrast, the F-22 only made up an average of around 22% of the aircraft procurement budget in its first five years of procurement.

If the Air Force follows the go-fast example of the F-15, most of the money for buying new aircraft would go towards the F-47 in the first five years of the program before leveling off to around 30% in later years. Based on trends in new aircraft procurement spending over the last ten years and assuming F-47 procurement begins two years after its first flight , the Air Force would spend an average of more than $10.5 billion per year from 2030 to 2035 on the new fighter by following the go-fast model. For comparison, the Air Force spent an inflation adjusted average of nearly $6 billion annually on the F-35A procurement from 2020 to 2025.

The primary benefit of the go-fast model is that it gives the Air Force significantly more sixth-generation fighters sooner. Assuming a high-end unit cost of $300 million, the go-fast model could give the Air Force around 210 F-47s by 2035. The main downside of this approach is that programmers may have to reduce funding for other major aircraft acquisition programs to account for increased spending on the F-47.

Alternatively, the Air Force could follow the F-22’s go-steady model and keep the proportion of F-47 funding constant at around 30% of its aircraft procurement budget. Taking the go-steady approach with the F-47 would not be an aberration in historical spending patterns. Under this model, the Air Force would spend an average of about $5 billion from 2030 to 2035 on the F-47, which is below the annual average it spent buying F-35As from 2020 to 2025. The go-steady approach would lead to fewer F-47s entering service in the first five years of procurement than the go-fast model — only 100 fighters compared to around 210 — but it would leave funding available to continue to buy other types of aircraft.

The two models highlight the main tradeoff facing the Air Force when it comes to the F-47: should it prioritize getting as many new fighters as soon as possible, at the expense of acquiring other aircraft?

Without considerable and consistent increases to the aircraft procurement budget, the importance of other aircraft programs makes the F-22’s go-steady model better for the Air Force’s future needs. The Air Force cannot risk shifting funding from important aircraft procurement programs — like the B-21, collaborative combat aircraft (CCA) and air mobility aircraft — to the F-47.

CCAs have been developed in part to bolster the capabilities of the F-47 at a much lower cost, so cutting the CCA fleet for more F-47s would be entirely counter to its intended purpose. The F-47 lacks the strike capacity necessary for the Indo-Pacific compared to the longer-range and higher-payload B-21. Plus, the bomber’s role in the air leg of the triad makes the B-21 crucial to maintaining nuclear deterrence. Dedicating a greater proportion of spending to the F-47 could also force the service to reduce the planned expansion and upgrade of its tanker and cargo aircraft inventories, thereby further limiting an already-constrained fleet of crucial enablers .

Some may see an increase in the budget as a panacea for F-47-related budget tradeoffs. Yet, Congress’ appetite for higher defense budgets appears to be waning after a recent historic uptick in defense spending. Throwing money at the problem will not suffice even if Congress revives their interest in higher defense spending, as the F-47 would still compete with other expensive priorities for funding, like Golden Dome or Golden Fleet .

The Air Force needs to assess its F-47 plans to keep ahead of China’s growing air superiority capabilities. Historical lessons from the F-15 and F-22 can help the service anticipate the decisions it will face when acquiring the F-47. If the Air Force can learn from the past, it can acquire a significant number of F-47s without sacrificing other critical aircraft procurement programs.

Casey Nicastro is a Senior Analyst at the Center for Strategic and Budgetary Assessments. His work primarily focuses on the defense budgets and force structures of the United States and its allies.

图中所示为下一代空中优势（NGAD）平台，即F-47战斗机的图形渲染图。（美国空军图片）

美国空军需要对其战斗机做出一些艰难的抉择，以避免将制空权拱手让给中国。两款新型隐形战机已出现在中国领空，而歼-20战机不断提高的产量意味着到2030年，中国可能拥有多达1000架第五代战斗机。

空军的 F-47 有望帮助抵消中国取得的一些优势，但这只有在五角大楼的规划者就新型战斗机的支出、购买数量和购买时间做出明智的决定时才能实现。

F-15 和 F-22 的历史表明，空军在追求 F-47 的过程中将面临一些选择，并揭示出，虽然空军应该考虑购买更多这种新型战斗机，但仓促采购可能会以牺牲空军的其他采购优先事项为代价。

空军仍在研究如何制定F-47的成本和采购计划。每架飞机的成本估算从不到1亿美元到高达3亿美元不等。除了将2028年定为首飞目标外，F-47的采购计划几乎没有被提及。

目前尚不清楚美国究竟计划采购多少架F-47战斗机。2023年，时任空军部长弗兰克·肯德尔曾表示，空军计划采购约200架当时被称为下一代空中防御系统（NGAD）的战机。但那是在特朗普政府将该战机项目授予波音公司之前，而且此后几年积累的实战经验也可能改变这一数字。不过，为了便于讨论，我们暂且假设采购数量为200架。

以往在F-15和F-22上的支出情况有助于我们了解F-47的成本问题。从1973年到1991年，美国空军采购了1000多架F-15战斗机，按2027财年美元计算，经通胀调整后的平均单价接近8400万美元。在此期间，F-15的采购经费平均约占空军飞机采购预算的32%。从1999年到2009年，美国空军采购的F-22战斗机不足200架，平均每架价格为2.91亿美元（按2027财年美元计算）。这占空军飞机采购预算的27%。无论单架F-47的成本更接近高估值还是低估值，历史数据显示，空军应该预期该战斗机项目将占其年度飞机采购预算的约30%。

如今对华威胁的认知和战略重点更接近冷战时期，而非全球反恐战争时期。因此，空军应采购比当年F-22更多的F-47战机。自冷战以来，隐身技术、网络技术和弹药技术的进步意味着空军也无需采购超过1000架F-47。近期分析建议，至少采购300架F-47即可满足应对中国所需的作战需求。无论具体细节如何，空军应将200架F-47视为最低采购量，而非上限。

三个演习证明了反无人机系统（C-UAS）的一种新方法。

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F-15 和 F-22 也为美国空军提供了两种不同的 F-47 采购方案：“快速推进”或“稳步推进”。F-15 采购的前五年平均消耗了空军飞机采购预算的一半以上。相比之下，F-22 在采购的前五年平均仅占飞机采购预算的 22% 左右。

如果空军效仿F-15的快速研发模式，那么在F-47项目启动后的前五年，大部分新飞机采购资金将用于该项目，之后几年将稳定在30%左右。根据过去十年新飞机采购支出的趋势，并假设F-47的采购工作在其首飞两年后开始，那么按照快速研发模式，空军在2030年至2035年间平均每年将在新型战斗机上花费超过105亿美元。相比之下，空军在2020年至2025年间，经通胀调整后，平均每年在F-35A采购项目上的支出接近60亿美元。

快速交付模式的主要优势在于，它能让空军更快地拥有数量显著更多的第六代战斗机。假设单价达到3亿美元，那么到2035年，快速交付模式可以让空军拥有大约210架F-47战斗机。这种模式的主要缺点是，为了弥补F-47项目支出的增加，项目组可能不得不削减其他主要飞机采购项目的资金。

另一种选择是，空军可以效仿F-22的“稳步推进”模式，将F-47的资金比例保持在飞机采购预算的30%左右。对F-47采取“稳步推进”策略并非打破历史支出模式。根据该模式，空军在2030年至2035年间平均每年在F-47上的支出约为50亿美元，低于2020年至2025年间采购F-35A的年均支出。与“快速推进”模式相比，“稳步推进”模式会导致F-47在采购后的前五年服役数量较少——仅有100架，而“快速推进”模式则约为210架——但它可以确保剩余资金用于继续采购其他类型的飞机。

这两个模型凸显了空军在 F-47 问题上面临的主要权衡：是否应该优先尽快获得尽可能多的新型战斗机，而牺牲其他飞机的采购？

如果飞机采购预算没有大幅且持续的增长，考虑到其他飞机项目的重要性，F-22 的稳步推进模式更符合空军未来的需求。空军不能冒险将资金从重要的飞机采购项目（例如 B-21、协同作战飞机 (CCA) 和空中机动飞机）转移到 F-47 上。

CCA战机的研发部分原因是为了以更低的成本增强F-47战机的性能，因此削减CCA机队规模以增购F-47战机将完全违背其研发初衷。与航程更远、有效载荷更高的B-21轰炸机相比，F-47战机缺乏在印太地区所需的打击能力。此外，B-21轰炸机在三位一体核力量的空中部分扮演着至关重要的角色，对于维持核威慑至关重要。将更多资金投入F-47战机也可能迫使空军削减其加油机和运输机的扩充和升级计划，从而进一步限制本已捉襟见肘的关键保障机队。

有些人可能认为增加预算是解决F-47相关预算权衡问题的灵丹妙药。然而，在近期国防开支出现历史性增长之后，国会对增加国防预算的热情似乎正在减弱。即使国会重燃增加国防开支的兴趣，仅仅增加资金投入也无济于事，因为F-47仍将与其他耗资巨大的优先项目（例如“金穹顶”或“金舰队”）争夺资金。

为了应对中国日益增强的空中优势，空军需要重新评估其F-47采购计划。F-15和F-22的历史经验可以帮助空军预见在采购F-47时将面临的决策。如果空军能够吸取过去的经验教训，就可以在不影响其他关键飞机采购项目的前提下，采购相当数量的F-47。

凯西·尼卡斯特罗是战略与预算评估中心的高级分析师。他的工作主要集中在美国及其盟国的国防预算和兵力结构方面。