As a general rule, NATO air forces tend to retire their fighter jets long before those airframes reach the end of their service lives, although there are some important exceptions. Perhaps the US Navy is one of the most significant exceptions to this tendency. This is partly due to the massive stress placed on the aircraft airframes, where every aircraft-carrier-based launch is that of a catapult and every landing resembles that of a controlled crash.

The worn-out condition of the Navy’s fighter jets is one reason these aircraft are rarely exported second-hand. Another thing to keep in mind is that there is no hard ‘end of flight hours’ for a given aircraft. It is possible to carry out life-extension programs on many fighter jets.

Sometimes nations will run their aircraft into the ground. One of the issues currently between Ukraine and Poland (a NATO member) over the deal to transfer the last nine MiG-29s is that those jets are so worn out that they need an expensive overhaul. Here are some reasons why Western air forces often retire fighter jets long before they run out of flight hours.

Fighter Jets Become Obsolete Or Old

Many Western jets are designed for 8,000 flight hours

Credit: Department of Defense

One of the leading reasons that Western air forces often retire fighter jets before their airframes are exhausted is that they want to upgrade their capability. This is something similar to upgrading to a new smartphone before the old phone stops working. Examples include Belgium, the Netherlands, Norway, and Denmark all replacing their F-16AMs with new F-35As.

The F-35A presents a major leap in capabilities over the legacy F-16AMs that were built more than 40 years ago. It is considered too expensive and surplus to their requirements to keep the old F-16s in service or in storage. These smaller countries consider it better to retire them and sale/donate them to other countries so that they can focus their limited resources on sustaining their new F-35A fleets.

Australia provides a similar example to those European states, while Canada provides a counterexample. Australia retired all of its legacy Hornets in 2021, leaving it with a fleet of more modern F-35As, Super Hornets, and Growlers. Canada purchased a large share of these retiring Hornets, initially as a source of spare parts to keep its legacy Hornets operating, and then as flyable airframes. Canada is an example of a NATO country pushing its fighter jets as much as possible before replacement.

While the US Air Force has upgraded many of its F-16s with technologies associated with fifth-generation fighter jets, there is only so much that can be done to upgrade legacy airframes (they can’t be stealth fighters). The US is able to operate upgraded 4.5-generation fighters alongside stealth fighters. However, it is more difficult for smaller air forces to sustain mixed fleets.

Rising Costs Of Maintenance

The F-15C costs approximately $27,900 per flight hour

Credit: Shutterstock

As older aircraft age, they become increasingly difficult to maintain and keep airworthy. This leads to a range of issues. Canada is an example of a country that fell into the vicious cycle of holding onto its aging aircraft for longer, which drove up the cost of maintenance, which demanded a greater share of the budget, which left less money available for procuring new aircraft. This is now changing with Canada seeing purchasing new fighter jets as a priority.

Older aircraft tend to have more problems and issues, which leads to increased downtime and lower availability. Low availability is one of the biggest issues in many air forces. Sustainment costs per flight hour climb steeply in the last years of service, something termed the ‘long tail’ of fleet costs. At some point, it makes economic sense to replace the aircraft with new aircraft.

Over time, it can become increasingly difficult to purchase spare parts. The fighter jet may have been out of production for decades, and the supply chain may have vanished or withered. Many suppliers may have gone out of business, while those who haven’t may no longer possess the machinery to manufacture the parts.

It is common for older military aircraft to spend their last years in a state of cannibalization. Ever more airframes are retired and stripped for parts to keep an ever-shrinking share of the fleet operational. It is one of the major roles of the massive US boneyard at Davis-Monthan. Retired A-10s, B-1Bs, F-16s, etc are stripped for parts to keep remaining articles viable for longer.

Geopolitical & Industrial Considerations

The final order for 17 Super Hornets will keep production going until 2027

Credit: Shutterstock

It is important not to see air forces as isolated islands; they exist in a much larger industrial and geopolitical context. It is generally considered in the national interest to keep a national fighter production line humming, as when it is shut down, the capability withers, and it can be incredibly difficult to restart.

The United Kingdom needs to keep its Eurofighter Typhoon production line working until it can switch over to building the sixth-generation GCAP/Tempest currently under development. In this case, exports from Turkey are helping bridge the gap, as are workshares on Italian, German, and Spanish orders. This relieved pressure on the UK to purchase Eurofighters for the RAF just to keep the line working.

By contrast, keeping Boeing’s industrial ability to produce fighter jets was a key reason that Congress provided funds to purchase more Super Hornets than the Navy wanted. This bridges the gap for Boeing to switch over to programs like the F-47, MQ-25, and MQ-28. Having surplus new Super Hornets increases the motivation in the Navy to retire existing aircraft early.

There are also wider geopolitical considerations. Indeed, Sanctions placed on Russia in 2014, 2017 (via CAATSA), and 2022 have made it much more difficult for countries to service their Russian/Soviet fighter jets and helicopters.

One example is Colombia and its issues servicing its fleet of Mi-17 helicopters. This has sped up a transition away from Russian fighter jets and helicopters. Meanwhile, the retirement of the US Marine Corps’ AV-8B Harrier II fleet in 2026 increases pressure on the Italian and Spanish navies to phase theirs out as maintenance becomes more complicated.

Peace Dividend & Return To Rearmament

Germany has ordered 58 Eurofighters & 35 F-35s

Credit: Department of Defense

Historically, a major reason for NATO air forces to retire their fighter jets early was the so-called peace dividend following the end of the Cold War. With the collapse of the USSR, NATO air forces suddenly found themselves with large and expensive fighter jet fleets that were built to take on an adversary that no longer existed.

During the 1990s, many Western fighter jets were retired early as military budgets were slashed. This is also true for Russia (and Ukraine), which moved to retire vast numbers of its Soviet inheritance that it couldn’t financially maintain. With a return to a Cold War-like reality, NATO countries are again rearming, with many moving to double their defense budgets.

Paradoxically, rearming can also have the effect of retiring fighter jets early. Countries that are rearming, like Germany, find themselves with aging fighter jets like the Panavia Tornado that are increasingly seen as inadequate in a future high-end conflict. Germany is moving to purchase more modern fighter jets like F-35s and Eurofighter Tranche 5s.

However, expanded budgets only go so far. Air forces have limited resources that extra funds still struggle to solve. One major issue in modern air forces is a limited number of trained pilots. There are enormous bottlenecks in substantially increasing the pool of available pilots, as well as the oft-forgotten maintainers. This creates pressure to concentrate scarce personnel on newer aircraft rather than continuing to devote pilots and maintainers to increasingly expensive legacy fleets.

Balancing Domestic Needs With Allies

16 ex-Swedish Gripen Cs and 53 ex-Belgium F-16s for Ukraine

Credit: Department of Defense

There are many reasons why Western air forces may retire their fighter jets early, and it is not possible to list them all here. However, perhaps one interesting case that has become more acute since 2022 is the need to supply allies, with Ukraine being the leading example. This has not been a major factor in retiring aircraft early, but it has been a factor.

Poland and Slovakia parted with their MiG-29s (half of Poland’s fleet) ahead of schedule in 2023. It should be stressed that replacements were already in the pipeline; the question was simply one of timing. The issue was such in Slovakia that when the Ukraine-skeptic opposition was elected to power, it opened an investigation into the actions of the previous government and whether the early donation created a gap in Slovakia’s capabilities. The case was later closed, concluding it didn’t.

Elsewhere in Europe, there is some pressure on France to retire more of its aging Mirage 2000-5s a little early to donate to Ukraine, as well as in Sweden. Sweden stated in 2026 that it will send 16 older Gripen Cs starting in early 2027. The Swedish Air Force is already receiving replacement Gripen Es, but it is under some pressure to speed up the retirement/donation timeline of legacy jets.

There is an irony here. Belgium was initially reluctant to transfer its F-16s, ostensibly because of concerns about their age and condition, yet it is now on course to become Ukraine’s largest supplier of F-16 fighter aircraft. The episode illustrates an important point: an aircraft can be considered too old or too expensive to retain as a front-line asset by one air force while still being sufficiently useful to another air force that is willing to accept the associated maintenance burden.