The United States Air Force will use a mix of fighter aircraft, namely the F-15EX, F-22, F-35, and F-16 to fill the role of steadily retiring F-15C/D and F-15Es. The aging Eagle air superiority fighters are being rotated out of various bases, including Kadena Air Base in Japan. F-16s are being used as a cost-effective way to maintain airpower while the number of F-15EX and other platforms are increased later on.

The latest iteration of the awesome Eagle is the F-15EX. As the successor to one of the most complex and successful US fighters ever developed, it has several advantages, including increased payload capacity, advanced avionics, and the ability to carry an even wider range of weapons. It leverages an existing production line and new tech that has emerged since the F-15 debuted in 1972 to be both an affordable and highly effective recapitalization of the fighter fleet.

A New Mixed High-Low Fighter Fleet

The Boeing F-15EX Eagle II, Lockheed Martin F-22 Raptor, and F-35 Lightning II represent high-end, more capable, and expensive platforms. On the low-end, the F-16 is considered a more affordable and versatile platform. This fleet composition strategy has existed for decades, but it is being implemented anew as the USAF is faced with a more urgent need to recapitalize its fighter fleet.

The F-15C/D has been a dedicated air superiority fighter for decades, while the F-16 served alongside a multirole fighter designed for both air-to-air and air-to-ground missions. The F-15EX takes multi-role to a new level with advanced avionics, a huge weapons payload, and a higher performance than ever before. It is designed to replace the remaining legacy Eagle models and complement the F-22 and F-35 in air defense and strike missions as a kind of “weapons truck.”

The F-35 maximizes the advantages of stealth, advanced sensors, and data fusion to penetrate enemy airspace undetected. It operates as a node in a larger network, sharing data and coordinating with other assets for enhanced combat effectiveness. The F-35 can still perform many missions itself, including air superiority, ground attack, and electronic warfare.

The F-22 Raptor is the ultimate air superiority fighter and remains unchallenged as the penultimate US fighter. The F-22 has all of the power, speed, and maneuverability of the F-15 plus the stealth and sensors capability of the F-35. The F-15EX is a mature platform with a well-established maintenance and logistics infrastructure that can be adapted for various roles. As a combined force, these platforms comprehensively fulfill the myriad mission requirements the USAF and US Armed Forces demand.

Breaking Down The Theory

The high-low fleet portfolio in the Air Force can be very confusing in its exact meaning. Generally, the F-16 or A-10 Warthog is considered the low-end component of a high-low mix due to its simpler design and lower cost. This method of definition is considered flawed by some, like War On The Rocks, as it does not account for the mission context that defines the true high-low dynamic purports to be. It is not the low price tag or high volume of A-10s that make F-15C or F-22 fighters better at achieving air superiority. It is actually because the A-10 has a narrow mission scope and is tailor-made for that job.

Packaging the Warthog's, or Fighting Falcon’s, unique attributes within a blend of complementary mission-specialized and multi-role aircraft makes the overall team stronger than it would otherwise be. That method of classification is also going away, however, as virtually all aircraft are multi-role. A good methodology for 2025 would be using generations: fourth-gen, fourth-gen-pus, and fifth-gen fighters are all significantly different in capability, complexity, and cost.

At the tactical level, new platforms’ delayed entry to service is a major force of detriment. This is often the result of creeping complexity and leads to the erosion of combat advantages. The development program of the F-35 was intended to overcome this spiral effect. However, the original F-35 program fell far behind schedule, and some say that it only entered service after largely watering down the requirement of what defined combat-capable.

Where Does NGAD Fit In?

The recently announced Boeing F-47 is the product of the Next Generation Air Dominance (NGAD) program. It will be a sixth-generation fighter designed to replace the F-22 Raptor, the current apex-predator, air superiority fighter. It incorporates advanced stealth, sensors, and drone wing coordination, offering a significant leap in capabilities compared to the F-22. The F-47 is capable of working in concert with uncrewed Collaborative Combat Aircraft (CCA) in manned-unmanned mixed combat scenarios.

Its "built to adapt" philosophy is intended to allow for frequent updates and modifications. Air & Space Forces Magazine reported that in written testimony, Secretary of Defense Pete Hegseth promised the F-47 will be:

“[The] most advanced, lethal, and adaptable fighter ever developed, with state-of-the-art stealth technologies to stay one step ahead of America’s adversaries. The F-47 will have significantly longer range, more advanced stealth, be more sustainable, supportable, and have higher availability than our fifth-generation fighters. [The] platform will also take significantly less manpower and infrastructure to deploy.”

The F-47 is expected to be cheaper to produce and maintain than the F-22, allowing for a larger fleet. The F-15EX is being acquired to replace the remaining F-15C/Ds, with the F-47 focusing on air superiority and deep-penetration missions. The F-15EX is designed for homeland defense and air defense missions, while the F-47 is focused on air superiority and deep-penetration missions.

Changing Of The Guard

Since the start of the F-15C/D's phasing out in 2022, the Air Force has been rotating fourth- and fifth-gen fighters, including to reconstitute Kadena Air Base's fleet. The F-35As have already arrived, and the F-15Es will likely be swapped out for other fighter squadrons later this year. The latest rotation of F-35 Joint Strike Fighters (JSF) arrived at Kadena Air Base in April 2025, marking the latest as the base awaits its new permanent F-15EX fleet.

Major Chris Burson, 336th Fighter Generation Squadron commander, commented to Air & Space Forces magazine:

“We are looking forward to putting our skills and training to the test and taking our mission execution to the next level here on Okinawa. Kadena is a fantastic opportunity for us—working alongside our mission partners, sharing experiences and techniques, will be invaluable and will ensure we are an effective fighting force in the Indo-Pacific.”

The combination of fourth- and fifth-generation fighters at the strategic US outpost in the western Pacific is aimed at "deterring potential adversaries." The 18th Wing expects its first batch of EX fighters to arrive between March and June 2026. The ongoing fighter rotation at Kadena will continue until the base achieves full operational capability.

The Fighter Fleet’s Snowballing Issues

The Air Force's current fighter inventory is aging and increasingly inadequate, with the majority consisting of planes designed in the 1960s and '70s. Now averaging three to four decades old, even relatively new F-15Es average 30 years, meaning lower readiness levels as required downtime for repair eats into mission capability.

Today, the Air Force has less than half the fighter inventory it had in 1990. Operational demand has never abated, as the number of fighters decreased, but the workload actually increased through decades of conflict in Iraq and Afghanistan. Older fighters are now physically worn out and must be retired, but the Air Force has not been funded to procure a sufficient volume of replacements.

The Air Force now needs to buy new fighters at an aggressive rate and to procure the right mix of capabilities to ensure the force will remain relevant over the long term. The Next Generation Air Dominance (NGAD) fighter will not enter service until the 2030s. Lawmakers on both sides of the aisle have highlighted the fact that the Air Force planned to retire over 600 fighters over the next five years, while acquiring just 246, and that shortfall was never the plan.

America’s Aging Fifth-Gen Jets

The F-22 is a vital fifth-generation air superiority aircraft designed to fly and fight in contested airspace against near-peer adversaries. It will remain in the inventory until NGAD arrives in the next decade. NGAD promises to be extremely capable but also costly. That suggests a limited inventory of NGAD aircraft. That will continue to leave a capability gap as demand remains high across a range of global theaters, and new emerging threats are continuously changing.

The F-35 is the key to the Air Force's fighter modernization strategy, offering a mix of advanced capabilities, including survivability against advanced threats and the ability to empower the information battlespace with improved sensors, processing power, and connectivity. It is competitively priced compared to the F-22 and F-47, which has allowed for mass procurement to ramp up and meet the Air Force's capacity requirements.

Air Force officials still contend that the service's capacity solution is not as simple as procuring F-35s at a faster rate. The Air Force also does not want to ramp up production further until TR-3 and Block 4 capability is available, as these upgrades have been slower to field than planned. The F-15EX will be vital in the future as a complement to the F-22, F-35, and F-47 to achieve fleet readiness and capability through combined qualities.