Why does the US Air Force still rely on the F-15E Strike Eagle for its precision strikes, despite the F-22 and F-35 stealth aircraft?
In summary
The F-15E Strike Eagle is often described as the US Air Force’s “workhorse.” Behind this image lies a conscious doctrinal choice: to continue using a heavy 4th generation twin-engine aircraft to strike far, often, and with a massive payload, even though the United States has 5th generation stealth aircraft at its disposal. The F-15E can carry up to approximately 11 tons of weapons, has a range of over 1,200 kilometers with refueling, and was designed to fly low, at night, and in all weather conditions thanks to the LANTIRN system. In contrast, the F-22A and F-35A are optimized to penetrate the densest defense bubbles, but with less ammunition and at a higher cost per flight hour for the former. The USAF therefore balances firepower, availability rates, the resilience of a depreciated aircraft, and the scarcity of stealth platforms. This mix shapes the American deep strike doctrine, where the F-15E remains the everyday workhorse, and stealth aircraft are the scalpels reserved for the early hours of the most contested conflicts.
The F-15E, a workhorse designed to strike from afar
The F-15E is derived from the F-15 Eagle but has been completely redesigned for air-to-ground missions. Twin-engine and two-seater, it combines a airframe capable of reaching Mach 2.5 (approximately 2,650 km/h) at 18,000 meters, with conformal fuel tanks (CFT) and up to three external tanks, giving it a range of around 1,200 to 1,300 kilometers in combat configuration, and more than 3,800 kilometers in transport configuration.
Its maximum payload exceeds 11,000 kilograms, carried on 15 hardpoints. It can carry a combination of 900 kg JDAM guided bombs, 250 kg bombs, Small Diameter Bombs, and air-to-air missiles for self-defense. When fully loaded, a single F-15E can engage multiple high-value targets or saturate an area with precision-guided munitions.
The core of its night mission capability is the LANTIRN (Low Altitude Navigation and Targeting Infrared for Night) system, a set of two pods mounted under the air intakes. They provide very low-altitude navigation, radar terrain following, infrared imaging projected onto the HUD, and laser target designation. In other words, the crew can fly a few hundred feet above the ground, at night and in bad weather, while dropping guided bombs with great precision.
Firepower and cost per target: the economics of striking
In budgetary terms, the comparison is less intuitive than it seems. The Pentagon’s reimbursable cost data for fiscal year 2022 indicates an hourly cost of approximately $18,800 to $19,700 for the F-15E, compared to approximately $13,200 to $13,800 for the F-35A, and over $50,000 for the F-22A.
Taken in isolation, the F-15E is more expensive per hour than an F-35A. But when you consider the cost per target, the picture changes:
- an F-15E can carry up to eight 900-kg JDAM bombs, or even more lighter munitions;
- an F-35A, in internal stealth configuration, is limited to four 900 kg bombs or a larger number of smaller bombs, but still falls far short of the Strike Eagle’s weapon load;
- in external non-stealth configuration, the F-35A regains a significant payload, but loses most of its stealth advantage.
If a deep strike mission requires dealing with a dozen or so fixed targets that have already been clearly identified, sending two heavily loaded F-15Es may be less expensive overall—in terms of flight hours and aircraft mobilized—than increasing the number of sorties by stealth platforms. This explains the widespread use of the F-15E in Iraq, Afghanistan, and Syria, where the ground-to-air threat was limited to medium- and short-range systems.
The availability and resilience of a 4th generation aircraft
A cost-effective and optimized aircraft
Logistically, the F-15E benefits from decades of operation. The maintenance chain is well-established, parts are available, and mechanics are thoroughly familiar with the airframe. Studies conducted in the 1990s highlighted its ability to generate more than one sortie per day per aircraft at a sustained pace, with an availability rate of over 80% during operational trials.
Above all, the F-15E is a “depreciated” aircraft: development costs are behind us, infrastructure is in place, and simulators exist. Each flight hour remains expensive, but the economic model is stable. This allows for continuous combat rotations without wearing down a numerically limited fleet, as is the case with stealth aircraft.
At the USAF level, there are just over 200 F-15Es, compared to fewer than 200 F-22As and only a few hundred F-35As in service, while the 4th generation fleet (F-16, F-15C/D, F-15E) numbers in the thousands. This relative abundance makes the Strike Eagle very attractive when it comes to producing long-term effects.
Growing vulnerability to modern defenses
This picture is not without its drawbacks. In an environment saturated with modern radars, long-range surface-to-air missiles, and passive detection systems, an F-15E remains a large 4th generation aircraft, highly visible on the radar and infrared spectrum.
The tactics employed—low-altitude flight, night approaches, systematic use of jammers—reduce the risk, but do not eliminate it. Faced with densely deployed S-400 or HQ-9 systems, the USAF increasingly considers the Strike Eagle as a “second curtain” tool, to be engaged after the first waves of air defense suppression have degraded the enemy.
The role of stealth aircraft in deep strikes
The stealth aircraft is not a replacement for the F-15E, but a complement to it. The F-22A is primarily an air superiority fighter, with limited but extremely accurate ground attack capability, mainly targeting radars, command centers, or aircraft on the ground. Its very high hourly cost and small fleet mean that the USAF uses it sparingly.
The F-35A, on the other hand, is designed as a multi-role stealth aircraft capable of entering A2/AD bubbles in the early hours to neutralize enemy surface-to-air systems, C2 nodes, and runways. It excels in this initial phase, where its stealth, data fusion, and sensors allow it to survive where an F-15E would have to remain out of reach.
But this stealth comes with constraints:
- more limited internal payload;
- flight envelope to be respected in order to maintain a low signature;
- more heavy surface maintenance.
In practice, the USAF tends to reserve its F-35As for missions where survivability takes precedence over weaponry, particularly during the early days of a campaign against a heavily equipped adversary. Once the defense has been weakened, the Strike Eagles resume their role as precision bomb trucks, supported by F-35s that continue to lead the way and provide tactical intelligence.
The USAF’s doctrinal compromises for the coming decades
The question is therefore not whether the F-15E is “better” than 5th generation aircraft, but how to articulate these capabilities in a coherent doctrine. For the time being, the USAF is adopting a mixed approach:
- relying on the F-15E for firepower, long night missions, and repeated strikes against known targets;
- using the F-35A for initial penetration, neutralization of surface-to-air threats, and support in contested environments;
- retaining the F-22A for high-intensity anti-aircraft warfare, while exploiting its strike capability on an ad hoc basis.
The arrival of the F-15EX, an evolution of the Strike Eagle, confirms this choice: rather than betting everything on the 5th generation, the USAF prefers to modernize a concept it has mastered, offering renewed avionics, AESA radar, and even greater carrying capacity for air-to-ground weapons and long-range air-to-air missiles.
One strategic question remains: in a high-intensity conflict against a power with modern integrated defenses, how long will an F-15E be able to continue flying “close enough” to deliver its bombs, even with escort and jamming? Conversely, in the majority of real-world operations—limited strikes, asymmetric theaters, coalition operations—the Strike Eagle’s economic and operational equation remains formidably effective.
As long as the USAF has to balance tight budgets, a scarcity of stealth platforms, and the need to strike quickly and hard in multiple theaters, American air deterrence will likely continue to rely on this 4th generation workhorse, supported but not replaced by the stealth gems that are the F-22 and F-35.
Sources (selection)
– U.S. Air Force, official F-15E Strike Eagle, F-35A Lightning II, and LANTIRN fact sheets.
– U.S. DoD, “FY 2022 Reimbursable Rates” (costs per flight hour for F-15E, F-35A, F-22A).
– National Interest, “Why America’s Adversaries Fear the F-15E Fighter,” August 2025.
– Air & Space Forces Magazine, “A Better Way to Measure Combat Value,” 2023.
– Centcom Citadel, “The F-15E Strike Eagle: A multirole work horse,” 2023.
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