Why The US Air Force Is Spending Nearly $1 Billion To Rebuild 1 Base For Just 21 F-15EX Jets

Published Sep 5, 2026, 6:00 PM EDT Aaron is an aviation enthusiast and world traveler with a deep interest in aerospace history and technology. He has traveled around the world numerous times, often incorporating visits to aviation museums and historic aircraft collections into his journeys. A native of New Zealand, he is an expert in aviation and maintains a broad interest in a variety of other subjects. One of the most underappreciated aspects of United States Air Force modernization and preparedness is the vast sums needed to upgrade air bases and airfields across the United States and in the East Pacific region. The US Air Force is expected to spend around $1.5 billion each on modernization of its Ellsworth and Dyess strategic bomber air force bases and large sums on Andersen Air Force Base in Guam, the airbases in Tintan just to the north, as well as rehabilitating various airstrips in the surrounding islands (like Peleliu in Palau). Included in the pool of airbases in need of being modernized is Selfridge Air National Guard Base (SANGB) in Michigan. With the phase-out and retirement of the A-10, the base is set to transition to the modern F-15EX fighter jets. This imposes hefty transitional costs on the airbase. Selfridge is also a major air refueling base, and the United States has as much as 75% of the world's tanker fleet, depending on what's counted. Here is what to know about Selfridge's major modernization programs. Michigan's Selfridge Air National Guard Base Credit: US Air Force Selfridge Air National Guard Base is a major air base in Michigan near Detroit on the border with Canada. The host unit is the 127th Wing of the Michigan Air National Guard. Its website says, "A powerhouse of air dominance and strategic agility—the 127th Wing operates both the A-10 Thunderbolt II and KC-135 Stratotanker flying missions. The 127th Wing stands as the only Air National Guard unit to host a military installation, Selfridge Air National Guard Base." It adds, "With over 1,400 elite Airmen, 45 mission partners, we defend the homeland and fuel global missions, with unmatched versatility and readiness." The A-10 Warthogs are being phased out. The Fiscal 2026 budget only requires the Air Force to maintain 103 examples, allowing 59 to retire in Fiscal 2026. The Air Force's Fiscal 2027 request calls for the retirement of half (49) of the remainder, keeping only 54 in service for a few more years. In 2025, it was announced that Selfridge's A-10s would be replaced by 21 modern F-15EX Eagle IIs. In Fiscal 2027 documents, it appears the Air Force is almost doubling its F-15EX procurement target to 267 examples. At the same time, the Air Force is investing more in expanding Boeing's production line to ramp up production numbers. The first F-15EXs are expected to arrive at Selfridge in 2028. Welcomed Investment By Michigan Credit: US Air Force In May 2026, the Detroit Regional Chamber stated it "Applauds" the "Senate unanimously passed House Bill 4572, a $152 million spending bill on a new runway at Selfridge Air National Guard Base." It says that Selfridge's sustained infrastructure upgrades are projected to cost around $1 billion over five to seven years. It adds that the base has the "immense potential" to become a "super base" in the years to come. It notes that in 2025, Speaker Hall and Gov. Whitmer asked President Donald Trump and Defense Secretary Pete Hegseth "for a new fighter mission for Selfridge, with the current mission wrapping up, and Trump then committed to 21 F-15EX aircraft for Michigan." In addition to the fund, Michigan has approved $162 million for Selfridge runway improvements, $24 million for Taxiway Bravo, and $28 million for Taxiway Alpha. Selfridge Air National Guard Base in numbers (per budget documents) Number of airmen stationed Over 1,400 Planned F-15EX complement 21 Planned KC-46A complement 12 State of Michigan investment $162 million Federal investment $792 million to $1 billion Overall, the US federal government is expected to commit $792 million to $1 billion toward hangars, maintenance facilities, KC-46 infrastructure, airfield upgrades, and support buildings. The State of Michigan will provide $152 million for the runways, taxiways, etc. Selfridge's Upcoming KC-46A Squadron Credit: Shutterstock The Air Force is not simply swapping out one type of fighter for another; it is effectively creating a new fighter and tanker complex. The State of Michigan's investment is mostly aircraft-agnostic, being runway and taxiway improvements. Meanwhile, around $190 million of the Federal government's funds are specifically for the F-15EX's eight-bay maintenance complex. A greater amount of the Federal funds is for the new KC-46A Pegasus tankers. Around $280 million is directly for KC-46 infrastructure, including a dual-base hangar complex, an aircrew training complex, and a squadron operations building. Selfridge is to host a squadron (12) of new KC-46A refueling tankers, with the first expected to arrive starting in 2029. In January 2024, the Air Force reported, "Twelve KC-46As are expected to replace the aging A-10C Thunderbolt IIs and KC-135 Stratotankers at Selfridge ANGB. The A-10s at Selfridge ANGB are expected to begin divestment in 2026, and the KC-135s there are expected to begin divestment in 2027." These KC-46s present a significant improvement over the aging KC-135s. At the time, the Air Force said that Selfridge was not precluded from being considered for new fighter jet missions; this was followed by 2025's announcement that F-15EXs would be based there. Credit: US Air Force Selfridge requires a large investment not only because it is transitioning to a new generation of aircraft, but also because its existing infrastructure is old. The F-15EX and KC-46A have different requirements than the aircraft they are replacing. There are other costs not included in the base cost associated with transitioning from one fighter jet type to another. Many of Selfridge's current A-10 pilots will need to undergo transition training to operate the F-15EX. Although the Air Force does not publicly disclose F-15EX conversion costs, training fighter aircrew generally costs many millions of dollars, making personnel qualification another significant element of the overall program. The F-15EX is a two-seater fighter with a pilot and a Weapon Systems Officer. Training the crews for the F-15EX is potentially more than the funds needed to upgrade Selfridge that are directly applicable to the F-15EX. The F-15EX's new $190 million complex is around $9 million per jet. Selfridge is an excellent example of why just comparing the fly-away costs of fighter jets (which many articles do without context) can be so misleading. The initial flyaway cost of a fighter jet is only a minority of the overall costs of operating a fighter jet capability. The combined costs of add-ons, munitions, upgrades/updates, base infrastructure, fuel, spare parts, maintenance, etc. represent a far greater cost over time. Maintaining Airbases Is Expensive Credit: US Air Force The Department of the Air Force (which includes the Space Force) is requesting $26.75 billion for military construction, family housing and facilities sustainment, restoration and modernization in Fiscal 2027, more than double the $13.06 billion enacted for Fiscal 2026. The funding reflects a major expansion of construction to support new B-21s, F-47s, nuclear modernization, Space Force growth, and other programs. The increase reflects the renewed emphasis on preparing for great-power conflict, as well as a recognition that modern combat capabilities require the basic infrastructure to operate, maintain, and disperse them. Another factor is that much of the infrastructure is aging from the Cold War. Some of the airbases with the most expensive upgrade programs include Nellis Air Force Base (over $1.6 billion), Ellsworth Air Force Base (around $1.3 to 1.5 billion), and others. Around $800 million is being spent to revive and upgrade airfields on the island of Tinian in the Northern Mariana Islands. This includes $409 million for North Field (an enormous abandoned WWII-era airfield) and $384 million for Tinian International Airport. These are considered the closest things to true 'backups' for Guam's Andersen Air Force Base. Other airfields in the region are mostly a mixture of dual-use international airports with minimal military infrastructure and austere airstrips earmarked for dispersion under the ACE doctrine. Space Force Is Bigger Michigan Investment Credit: NASA What is also interesting is that since being split off from the Air Force in 2019 as an independent service branch, the Space Force has continued to grow faster than the other branches. Speaking of the doubling in the Department of the Air Force infrastructure spending, the Air and Space Forces Magazine notes that it includes a tripling of Space Force military construction spending, which would rise from $570 million to nearly $1.8 billion. While the State of Michigan is contributing to the modernization of Selfridge, it is not the most expensive MILCON project going on in the state. Congressman John James writes, "The $162 million figure is also the 2nd largest appropriations for military construction overall, behind just one project for the Space Force that is larger." The federal Fiscal 2027 budget includes funding for a Space Force project worth around $192.5 million. In Fiscal 2021, the first year the Space Force had its separate budget, the request was for $15.4 billion vs $153.6 billion for the Air Force. In Fiscal 2027, the Space Force's budget request has swelled to $71.1 billion (+362%) while the Air Force has grown to $267.7 billion (+74%). By some estimates, the Space Force's budget would be enough to make it the seventh-largest military budget in the world, potentially between the United Kingdom and France (depending on how figures are counted).