F-35 Sale to Turkey: Re-Arming a Key NATO Ally
Few arms deals in modern history have generated as much diplomatic turbulence as the potential F-35 sale to Turkey. What began as a straightforward alliance partnership — Turkey ordering over 100 of Lockheed Martin’s cutting-edge stealth fighters — unraveled into one of NATO’s most consequential internal disputes. The reasons are complex, the stakes are enormous, and the situation remains unresolved.
At the heart of the controversy is a single decision Turkey made in 2019: buying a Russian-made S-400 air defense system. That choice triggered a chain reaction of exclusions, sanctions, and diplomatic tensions that continues to shape US-Turkey relations today. Now, with new political winds blowing through Washington and Ankara, the question of whether Turkey could ever re-enter the F-35 program is back on the table — and the answer is anything but simple.
A Brief History: From F-35 Partner to Program Exclusion
Turkey’s Early Role in the F-35 Program
Turkey wasn’t just a customer of the F-35 Joint Strike Fighter — it was a manufacturing partner. Turkish defense companies supplied critical components to the program, including airframe sections, cockpit displays, and center fuselage parts. Ankara had committed to purchasing more than 100 F-35A aircraft, positioning its air force for a generational leap in capability and cementing its role as a frontline NATO power.
This wasn’t a peripheral relationship. Turkey’s industrial participation represented hundreds of millions of dollars in contracts and deep integration into the global F-35 supply chain. For Lockheed Martin and the broader consortium, Turkey was both a buyer and a builder.
The S-400 Purchase Changes Everything
In 2017, Turkey signed a contract to acquire Russia’s S-400 Triumf surface-to-air missile system, and deliveries began in July 2019. Turkish President Recep Tayyip Erdoğan framed it as a sovereign defense decision — Turkey had sought NATO-compatible air defense systems but, according to Ankara, was denied adequate technology transfer terms by Western suppliers.
Washington saw it differently. Entirely differently.
The US objection went well beyond the optics of a NATO ally buying Russian military hardware. The core concern was technical and deeply serious: operating the S-400 alongside the F-35 would give Russian electronic systems an opportunity to profile and study the stealth jet’s radar signature, emissions, and operational behaviors. Essentially, the S-400’s radar could learn how to detect the F-35 — defeating one of the aircraft’s primary advantages and potentially compromising the security of every F-35 operating across NATO.
Put simply, the S-400 and the F-35 cannot coexist in the same operational environment without creating unacceptable intelligence vulnerabilities. This wasn’t about punishing Turkey — it was about protecting a $1.7 trillion program and the broader alliance’s air superiority edge.
Exclusion, Sanctions, and Supply Chain Fallout
In July 2019, the same month S-400 deliveries began, the United States formally removed Turkey from the F-35 program. Turkish defense companies lost their manufacturing contracts, costing Turkey’s defense sector an estimated $12 billion in projected revenue over the life of the program. The US had to scramble to find replacement suppliers for the components Turkey had been producing.
The consequences escalated further. In December 2020, the Trump administration imposed sanctions on Turkey’s defense procurement agency (SSB) under the Countering America’s Adversaries Through Sanctions Act (CAATSA). It was the first time CAATSA sanctions had been applied to a NATO member — a watershed moment that underscored just how seriously Washington viewed the S-400 purchase.
The Geopolitical Chessboard: Arguments For and Against F-35 Re-Engagement
Why Turkey Should Get the F-35
Turkey isn’t just any NATO member. It controls the Bosphorus and Dardanelles straits — the only maritime route between the Black Sea and the Mediterranean. It shares borders with Syria, Iraq, Iran, and Georgia. Its Incirlik Air Base has hosted US nuclear weapons for decades and served as a critical hub for operations across the Middle East.
Proponents of F-35 re-engagement make several compelling arguments:
– NATO’s southern flank needs strengthening. With Russian aggression reshaping European security, keeping Turkey firmly in the Western camp is a strategic imperative, not a diplomatic nicety.
– Pushing Turkey away accelerates its drift toward Moscow and Beijing. Erdoğan has already shown a willingness to engage both — F-35 exclusion has only accelerated that tendency.
– A modern Turkish air force serves NATO’s collective defense. An air force flying aging platforms is a liability, not an asset, on NATO’s most volatile flank.
– Economic and diplomatic leverage. An F-35 deal could come bundled with conditions — including meaningful movement on the S-400 question — that actually improve the security situation.
Why the F-35 Sale Remains Deeply Problematic
The opposing arguments are just as powerful — and they come from allies, not just adversaries.
The fundamental problem hasn’t changed: the S-400 is still on Turkish soil. Until Turkey decommissions or removes those systems, the technical threat to F-35 security remains. Selling the jets without resolving the S-400 question would essentially reward Turkey for its original transgression.
Greece and Israel — two of the US’s most important regional partners — have expressed serious concerns about advanced US weapons going to Turkey. Athens and Ankara have overlapping territorial disputes in the Aegean and Eastern Mediterranean, and Israeli defense planners have long factored Turkish military capabilities into their regional threat assessments.
Congressional opposition is substantial and bipartisan. Multiple US lawmakers have warned that any reversal on F-35 policy without concrete S-400 concessions from Turkey would set a dangerous precedent — signaling to other partners that CAATSA sanctions can be bypassed through political pressure.
Current Status and Alternatives: F-16s and Beyond
The F-16 Deal: A Strategic Compromise
In January 2024, the Biden administration approved the sale of 40 new F-16 Block 70 fighter jets and modernization kits for 79 of Turkey’s existing F-16s — a package valued at approximately $23 billion. The deal was widely interpreted as a carefully calibrated compromise: giving Turkey meaningful military hardware to modernize its aging fleet while stopping well short of the F-35.
The approval came after months of diplomatic maneuvering and was linked, at least implicitly, to Turkey’s eventual ratification of Sweden’s NATO membership. It demonstrated that US-Turkey defense cooperation hadn’t broken down entirely — but it also underscored the ceiling that the S-400 issue imposes on the relationship.
F-16 Block 70s are capable fourth-generation fighters, but they are not fifth-generation stealth aircraft. For a country that once expected to operate over 100 F-35s, the approval represents a significant step down in capability — and in symbolic terms, a reminder of what Turkey forfeited.
Turkey’s Indigenous Fighter: The TF-X Kaan
Partly in response to its F-35 exclusion, Turkey accelerated development of its own homegrown fighter jet. The TAI TF-X Kaan — also referred to as the MMU (Milli Muharip Uçak, or National Combat Aircraft) — made its first flight in February 2023. It’s an ambitious program with genuine potential, but it remains years away from operational capability.
The Kaan currently flies with a General Electric F110 engine — the same powerplant used in certain F-16 variants — because Turkey’s indigenous engine isn’t ready. Developing a competitive turbofan engine is one of the most technically demanding challenges in aerospace, and Turkey is still navigating that road.
This is where recent reports of Turkey moving closer to an “F-35 jet engine deal” become particularly intriguing. Analysts have speculated whether such an arrangement could involve Pratt & Whitney’s F135 engine — the powerplant that drives the F-35 — being adapted or licensed for use in the Kaan program. If true, this would represent a remarkable back-channel development: Turkey potentially accessing F-35 propulsion technology through its indigenous program rather than through direct jet purchases. The exact contours of any such arrangement remain unclear, but it signals that Turkey’s relationship with F-35 technology isn’t entirely severed.
Broader Implications for NATO and US-Turkey Relations
The F-35 saga exposes a fundamental tension at the heart of modern alliance management: What do you do when a critical ally behaves in ways that undermine collective security?
NATO operates by consensus, and Turkey’s presence in the alliance gives Ankara significant leverage. Erdoğan has wielded that leverage repeatedly — blocking membership bids, threatening to close Incirlik, and maintaining economic ties with Russia even as other NATO members imposed sweeping sanctions after the invasion of Ukraine. The F-35 exclusion hasn’t meaningfully changed this dynamic; if anything, it has given Turkey additional grievances to leverage at the negotiating table.
For the United States, the F-35 Turkey situation has also raised questions about its reliability as an arms supplier. Several partner nations have quietly noted that US weapons sales can be weaponized diplomatically — a factor that has led some countries to diversify their defense procurement portfolios.
The Trump factor adds another layer of uncertainty. During his first term, Trump oscillated between sympathy for Erdoğan’s position and firm statements against the sale. During the 2025 NATO summit in Ankara, reports indicated Trump opened the door to discussing F-35s again — only to face significant pushback from Republicans in Congress and from allied governments deeply opposed to the move. Whether that door remains open, and under what conditions, remains one of the more consequential open questions in transatlantic security.
What’s certain is that NATO’s internal cohesion suffers every time Turkey’s status as a “fractured ally” is on public display. The alliance’s credibility rests on member states trusting one another — and the F-35 controversy has made that trust visibly conditional.
Conclusion: Navigating a Fractured Alliance
The F-35 sale to Turkey is less a transaction waiting to happen and more a geopolitical riddle with no clean answer. Turkey is too strategically important to marginalize completely, yet the security concerns surrounding the S-400 are too serious to simply wave away.
The current reality — F-16s approved, F-35s firmly on hold — represents a pragmatic middle path. It keeps Turkey armed and engaged without crossing the red lines that would compromise the F-35 program’s integrity. But it doesn’t resolve the underlying tensions, and with political dynamics shifting in both Washington and Ankara, the situation remains fluid.
For the F-35 to ever return to the table in any serious way, at least one of two things needs to happen: Turkey must meaningfully address the S-400 issue, or the strategic calculus must shift so dramatically that the security risks are judged to be outweighed by the geopolitical costs of exclusion. Neither scenario seems imminent — but in the world of great power competition and alliance politics, “imminent” is rarely the right timeframe to watch.
The story of Turkey and the F-35 is, at its core, a story about the limits and contradictions of modern alliances — and it’s far from over.
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Frequently Asked Questions
Why was Turkey removed from the F-35 program?
Turkey was removed from the F-35 Joint Strike Fighter program in July 2019 after it began accepting deliveries of the Russian S-400 air defense system. The US determined that operating the S-400 alongside the F-35 would give Russian sensors the ability to study and potentially compromise the jet’s stealth technology — an unacceptable security risk for the entire NATO alliance.
Did the US sanction Turkey over the S-400 purchase?
Yes. In December 2020, the US imposed CAATSA sanctions on Turkey’s defense procurement agency (SSB), making Turkey the first NATO member ever sanctioned under the Countering America’s Adversaries Through Sanctions Act.
What fighter jets did Turkey receive instead of F-35s?
In January 2024, the US approved the sale of 40 new F-16 Block 70 fighter jets and modernization kits for 79 existing Turkish F-16s, in a deal valued at approximately $23 billion. This was widely seen as an alternative to F-35 re-engagement.
What is Turkey’s indigenous fighter jet program?
Turkey is developing the TAI TF-X Kaan (also called the MMU), a domestically produced combat aircraft that made its first flight in February 2023. The program is a direct response to Turkey’s F-35 exclusion, though it faces significant challenges, including developing a capable domestic jet engine.
Could Turkey ever rejoin the F-35 program?
It’s theoretically possible but unlikely in the near term. Most analysts agree that Turkey would need to decommission or remove the S-400 systems — and potentially lift CAATSA-related concerns — before any serious F-35 discussions could resume. Congressional opposition in the US remains strong, as does pushback from regional allies like Greece and Israel.
What are the NATO implications of the Turkey-F-35 dispute?
The dispute highlights tensions within NATO around burden-sharing, sovereignty, and the limits of alliance solidarity. Turkey’s partial pivot toward Russia and its use of its strategic position as diplomatic leverage has complicated alliance decision-making, while the F-35 exclusion has raised broader questions about the reliability of US arms supply relationships.