The single most striking figure in the current US airport investment debate is not the size of any one project: it is the gap. Airports Council International, North America (ACI-NA) estimates that US airports need $173.9 billion in infrastructure investment over the next five years, while the federal grant programme that has been filling a portion of that gap expires after FY2026, with no new funding authorised beyond it.
That contrast is what this analysis unpacks: how large the US airport investment wave really is, where the money comes from, and what the official figures say about whether it can sustain itself without fresh federal legislation.
How Big the Demand Side Actually Is
The investment case is made almost unanswerable by the passenger numbers alone. ACI-NA projects close to one billion US enplanements in 2025, climbing to 1.4 billion by 2040 and reaching 1.7 billion by 2050. At the same time, the FAA projects annual passenger traffic growth of 2.5% between 2023 and 2044, with an overall increase of 58% to approximately 1.28–1.3 billion annual passengers by 2040 sitting comfortably within that trajectory. To appreciate the scale of what is coming, the American Society of Civil Engineers (ASCE) reports that US domestic enplanements stood at 629.5 million in 2010, reached 811.4 million in 2019, and had recovered to 819.5 million by 2023: the system has already expanded considerably, and the projected growth on top of that existing base is of an altogether different magnitude.
The economic case is no less compelling. According to ACI-NA, US airports underpin 12.8 million jobs, with payroll across those roles totalling $619 billion annually and overall economic output reaching $1.8 trillion each year. Those are the figures that frame the organisation's latest report, which Kevin M. Burke, President and CEO of ACI-NA, titled "Modern Airports for a Stronger America: Unlocking Opportunities to Meet Soaring Demand."
What the Capital Programmes Look Like on the Ground
The mega-projects that anchor the current investment wave are individually enormous. Urbanize Chicago reports that O'Hare's $8.5 billion expansion has been pushed back to 2034, having originally been announced in 2018 with a 2026 completion date. The phasing within that programme illustrates the complexity: Urbanize Chicago reports that Satellite Concourse 1, adding 19 gates, is due to complete in 2028, the Global Terminal in 2032, and Satellite 2 in 2034.
JFK, LAX and Dulles are similarly multi-year undertakings. The collective scale of the large-hub programmes running through 2030 and beyond sits in the $145–155 billion range, which is itself only a portion of the $173.9 billion five-year need ACI-NA has identified.
The American Society of Civil Engineers (ASCE) puts precise numbers to the capacity pressure driving these commitments, drawing on the FAA's 2024 national capacity evaluation: 11 airports are forecast to face runway capacity constraints by 2028, with that figure climbing to 14 by 2033. The problem is compounded by the interaction between runway and terminal constraints, since adding gates without sufficient runway throughput, or increasing runway capacity without matching terminal provision, leaves the underlying bottleneck unresolved.
The Federal Funding Picture
The Infrastructure Investment and Jobs Act (IIJA) represented a significant step up. The American Society of Civil Engineers (ASCE) reports that the IIJA provided $25 billion in airport funding over five years. Within that, the Airport Terminal Program (ATP) provided approximately $5 billion in total to airports for terminal projects, according to the American Association of Airport Executives (AAAE).
Just how heavily airports have leaned on federal support is illustrated by the final ATP round. AAAE reports that 588 applications were submitted to the FAA seeking $7.1 billion in that final funding round, yet the FAA released only $970 million in FY2026 Airport Terminal Program discretionary grants, shared across 133 projects at 129 airports. Demand outstripped available funding by a factor of more than seven, a ratio that speaks plainly to the adequacy of the programme relative to the scale of need.
AAAE confirms that IIJA airport programme funding expires after FY2026, with no new funding made available beyond that year.
The Funding Gap: Three Ways to Read It
The gap calculations vary depending on the baseline assumption, and it is worth presenting all three figures from the official and industry sources rather than conflating them.
DWU Consulting (DWU AI) reports that ASCE's 2025 Infrastructure Report Card estimates US airport capital needs at approximately $310 billion over 2024–2033, up from the $237 billion ASCE had estimated for the prior decade in its 2021 report. That escalation in the assessed need is itself significant.
The scale of what is at stake financially is captured by ASCE's estimate of a $114 billion shortfall across the next decade if IIJA investment levels simply hold flat from 2026. Should federal investment slip back to pre-IIJA levels rather than remaining steady, DWU Consulting (DWU AI) reports that ASCE's calculation of the gap widens to $162 billion. The $48 billion separating those two figures represents the tangible value of sustaining IIJA-level federal commitment. As yet, no new legislation has been enacted to secure it.
One structural constraint compounds both scenarios. The Passenger Facility Charge, the per-ticket levy airports collect to fund capital projects, has been capped at $4.50 per enplaning passenger since 2000, according to ACI-NA, unchanged for a quarter of a century. Airports have no unilateral mechanism to close the gap: the PFC cap requires congressional action to lift.
What US Airport Investment Means for Passengers and the Industry
The passenger experience implications are direct. We have already noted, in our analysis of airport lounge overcrowding, that existing infrastructure is under visible strain even before the forecast growth materialises. If the funding gap widens and projects are delayed further, as O'Hare's expansion has already been, the mismatch between passenger volumes and available capacity will intensify before it improves.
For the industry more broadly, the picture sits alongside the cost pressures we have covered elsewhere, including the permanent shift in airline cost structures from pilot pay deals. Airports and airlines are both navigating elevated capital and operating costs at the same time as demand grows. Use our Airline Search to track how individual carriers are positioned across the airports at the centre of these programmes.
The Bottom Line
The official figures do not show a funding cliff so much as a funding slope: the gap exists now, it widens if federal investment falls, and it widens further still if the PFC cap remains unchanged. ACI-NA's $173.9 billion five-year estimate and ASCE's $310 billion decade estimate are not projections designed to alarm; they are assessments of what is physically required to match the passenger growth that the FAA's own traffic forecasts anticipate. The investment wave is real and large. Whether the financing structures exist to sustain it beyond FY2026 is, on the current evidence, an open question that only Congress can resolve.
This article draws on information from Airports Council International – North America (ACI-NA) and American Association of Airport Executives (AAAE) and reporting by DWU Consulting (DWU AI), American Society of Civil Engineers (ASCE) and Urbanize Chicago.
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