Turkey’s F-35 Return? How New Deal Could Reshape NATO Airpower
Few diplomatic puzzles in modern alliance politics are as technically complex and geopolitically loaded as the question of Turkey’s potential return to the F-35 program. What began as a straightforward partnership between NATO’s second-largest military and the world’s most advanced stealth fighter has become a years-long standoff involving Russian missile systems, threatened sanctions, congressional opposition, and competing visions for the future of Western airpower.
Now, with President Trump signaling he’s open to reconsidering Turkey’s F-35 ban — provided Ankara addresses its Russian missile system — the conversation has reignited with new urgency. The stakes couldn’t be higher. A successful deal would hand NATO a significant strategic boost on its volatile southern flank. A failed negotiation, meanwhile, could deepen one of the alliance’s most persistent internal rifts.
Understanding Turkey’s F-35 return requires peeling back layers of military technology, geopolitics, and domestic politics across three capitals. Here’s the full picture.
The F-35/S-400 Dilemma: How It All Began
Turkey’s Early Role in the F-35 Program
Turkey wasn’t just a customer for the F-35 Lightning II — it was a founding partner. Ankara joined the Joint Strike Fighter program in the early 2000s, committing to purchase 100 F-35A conventional takeoff and landing variants and actively participating in the aircraft’s manufacturing supply chain. Turkish companies produced components including fuselage sections, landing gear parts, and cockpit displays, creating both industrial investment and deep institutional ties to the program.
This partnership reflected Turkey’s ambition to modernize its air force into one of the most capable in the region. For NATO planners, a Turkish F-35 fleet represented a massive uplift for the alliance’s southern flank — the gateway between Europe, the Middle East, and Central Asia.
Why Turkey Bought the S-400
The relationship began to fracture around 2017 when Turkey announced it would purchase Russia’s S-400 Triumf (NATO designation: SA-21 Growler) long-range surface-to-air missile system. To understand why, you need to appreciate the frustration building in Ankara.
Turkey had sought a modern, long-range air defense system for years. Negotiations for the U.S. Patriot missile system repeatedly stalled over price, technology transfer, and co-production rights. Turkey wanted not just hardware, but the ability to manufacture and maintain the systems domestically — a condition Washington proved unwilling to meet on favorable terms. Russia offered a more accommodating deal.
There were also sovereignty signals embedded in the decision. President Erdoğan’s government had grown increasingly assertive about Turkey’s right to pursue independent defense relationships, viewing reliance on a single Western supplier bloc as a strategic vulnerability.
The Core Security Problem: Why the S-400 and F-35 Can’t Coexist
Here’s where the technical stakes become clear — and they’re significant enough to explain years of diplomatic deadlock.
The F-35’s most critical military advantage is its stealth capability: its ability to evade radar detection. This stealth profile is highly classified. The S-400 system uses an advanced active electronically scanned array (AESA) radar capable of tracking and analyzing airborne targets with sophisticated precision. The fear among U.S. defense officials isn’t simply that the S-400 could shoot down an F-35 — it’s that operating both systems in proximity could allow the S-400’s radar to “learn” the F-35’s stealth signature.
In practical terms, every time an F-35 operates near an active S-400 system, that system collects data. That data could potentially be transmitted back to Russia — giving Moscow’s engineers invaluable intelligence to help develop countermeasures against the very aircraft NATO relies on for air superiority. It would be, in the words of one defense analyst, like handing your enemy the blueprints to your most advanced weapon while you’re still deploying it.
The U.S. and NATO found this risk unacceptable. S-400 deliveries to Turkey began in July 2019, and Washington responded almost immediately.
The Expulsion and Sanctions
The U.S. officially removed Turkey from the F-35 program in July 2019, citing irreconcilable security concerns over the S-400. Turkish companies were cut out of the supply chain, costing Ankara both significant industrial revenue and the jets it had planned to build its future air force around.
The consequences escalated further. In December 2020, the Trump administration imposed CAATSA sanctions (Countering America’s Adversaries Through Sanctions Act) on Turkey’s Presidency of Defense Industries (SSB), marking the first time a NATO member faced such penalties. The sanctions targeted the agency’s leadership and restricted technology transfer and export licenses — a diplomatic rupture with no modern precedent in the alliance.
The “New Deal” Proposition: What Trump Is Considering
Fast-forward to the current political moment, and the signals from Washington have shifted notably. President Trump has publicly indicated he’s considering restoring Turkey’s access to the F-35 program. The condition attached is explicit: Turkey must address its S-400 problem.
Trump’s framing has been characteristically transactional. In his view, bringing Turkey back into the F-35 fold strengthens NATO against Russia and Iran — two adversaries whose influence concerns Washington. The strategic logic is straightforward: a fully-equipped Turkey with advanced Western fighter jets is a more capable NATO ally than one flying aging aircraft while operating Russian missile systems.
Senator Lindsey Graham, a prominent voice on defense policy, has echoed the view that closer U.S.-Turkey ties serve American strategic interests. But the pathway from political intent to actual deal involves navigating a minefield of technical, legal, and political obstacles.
What “Getting Rid” of the S-400 Actually Means
The central question — what Turkey would need to do with the S-400 — has multiple possible answers, each with different feasibility profiles:
– Return or destroy the systems: The cleanest solution from a U.S. security standpoint, but politically humiliating for Erdoğan, who staked significant domestic credibility on the purchase.
– Sale to a third country: Turkey has reportedly explored selling the S-400 to Pakistan or other nations. This removes the systems from Turkish soil but raises questions about where they land and who might operate them.
– Permanent deactivation: Turkey could theoretically mothball the S-400s, keeping them in storage without activating their radars. This is verifiable but reversible — a distinction that matters enormously to U.S. security officials.
– Software or technical isolation: Some analysts have proposed technical arrangements that would prevent the S-400 from networking with NATO systems or transmitting data to Russia. Most Western defense officials view this approach with deep skepticism, arguing that the hardware-level risk cannot be solved through software alone.
None of these options is politically painless for Ankara. Each represents a different calculation of what Turkey is willing to concede in exchange for F-35 access.
Why Turkey Needs the F-35 — And Soon
Turkey’s urgency around the F-35 question isn’t simply about prestige. It’s driven by genuine and growing airpower requirements.
An Aging Fleet Under Pressure
Turkey currently operates a fleet of F-16 Fighting Falcons, a capable but aging 4th-generation platform that faces increasing obsolescence against the advanced air defense systems and stealth aircraft proliferating across the Middle East and Eastern Mediterranean. Countries like Greece — with whom Turkey maintains a tense military rivalry — are acquiring F-35s, shifting the regional balance of air power in ways Ankara cannot ignore.
Regional Power Projection
Turkey’s military has become increasingly active across a wide geographic arc — from Syria and Libya to the South Caucasus and the Eastern Mediterranean. Projecting and sustaining airpower across these theaters demands a modern, multirole platform with extended range, advanced sensors, and stealth capabilities. The F-35 fills that requirement in ways no currently available alternative fully matches.
NATO Interoperability
Within NATO, the F-35 is rapidly becoming the alliance’s standard high-end air combat platform. As more member states operate the jet, shared tactics, data links, and coordinated air operations become increasingly F-35-centric. A Turkey flying F-16s while its allies fly F-35s faces growing interoperability gaps that undermine collective defense planning.
Economic and Industrial Stakes
Beyond military capability, Turkey has a financial stake in resolution. Turkish defense companies lost significant contracts when Ankara was removed from the F-35 supply chain. Reentry into the program would restore that revenue stream and potentially deepen Turkey’s defense industrial base — a major priority under Erdoğan’s policy of defense self-sufficiency.
How Turkey’s Return Would Reshape NATO Airpower
The strategic implications of a successful F-35 deal extend well beyond Turkey’s own military modernization. For NATO as a whole, the effects would be substantial.
Strengthening the Southern Flank
NATO’s southern flank — stretching from the Balkans through Turkey into the Black Sea and Eastern Mediterranean — is one of the alliance’s most complex and contested regions. Russian naval assets in the Black Sea, Iranian ballistic missile programs, and instability across the Middle East all create overlapping threat vectors. A Turkey equipped with F-35s would dramatically enhance NATO’s ability to project airpower, conduct intelligence, surveillance, and reconnaissance (ISR) missions, and respond to contingencies across this entire arc.
Burden Sharing and High-End Capability
One of NATO’s persistent internal tensions is the distribution of capable, high-end military assets. Turkey’s return to the F-35 program would represent a significant contribution to the alliance’s collective strike capability — and a meaningful step toward the burden-sharing that the U.S. has demanded from European allies for decades.
A Geopolitical Signal to Moscow
Perhaps as important as the hardware itself is what a deal would signal. Turkey’s S-400 purchase was widely interpreted as a strategic hedge — a demonstration that Ankara could maintain an independent relationship with Moscow outside NATO’s framework. Reversing that hedge by giving up or neutralizing the S-400 in exchange for F-35s would represent a visible realignment toward the Western security architecture. For Russia, which has invested heavily in using arms sales as diplomatic leverage, that would be a significant setback.
Challenges and Opposition: Why a Deal Isn’t Guaranteed
Despite the strategic case for Turkey’s return, the obstacles are formidable and the opposition in Washington is bipartisan.
Congressional Resistance
U.S. lawmakers have pushed back hard against any reversal of the F-35 ban. Their objections fall into several categories. First, there’s the unresolved security concern: until the S-400 issue is definitively resolved — not just politically promised — many members of Congress view restoring F-35 access as an unacceptable intelligence risk. Second, there’s the question of trust. Turkey has, at various points, blocked NATO initiatives, maintained economic ties with Russia during the Ukraine war, and pursued policies in Syria that put it at odds with its allies. For critics on Capitol Hill, the F-35 question is inseparable from this broader pattern of behavior.
Third — and perhaps most consequentially — is the precedent problem. If the U.S. reverses its F-35 ban without a complete, verified resolution of the S-400 issue, what message does that send to other NATO allies? The concern is that it could normalize the practice of purchasing Russian weapons systems while expecting to retain access to Western technology — a standard that would fundamentally undermine the alliance’s security architecture.
The Trust Deficit
Even if a technical solution to the S-400 problem is found, rebuilding the institutional trust between Ankara and Washington that existed before 2019 will take time. Defense partnerships require not just hardware agreements but shared assumptions about threat perceptions, operational security, and strategic alignment. That foundation has been damaged, and a single deal — however significant — won’t fully repair it.
The Geopolitical Chessboard: US, Turkey, and Russia
Turkey has cultivated what Erdoğan describes as a “strategic autonomy” — a foreign policy that maintains relationships with competing power blocs simultaneously. This approach has given Ankara unusual leverage: NATO needs Turkey, Russia wants Turkey, and Turkey has used that position skillfully.
A return to the F-35 program would represent the most significant tilt toward the Western security framework in Ankara’s foreign policy since the S-400 purchase. It would reduce Russia’s diplomatic leverage in Turkey and potentially reshape the broader US-Turkey relationship. For Washington, that realignment carries real value — but only if Turkey’s commitment is genuine and durable, not a tactical maneuver to extract concessions before returning to its hedging strategy.
The U.S. must also consider the message this sends to other regional actors. A Turkey with F-35s operating across the Eastern Mediterranean and Middle East changes the security calculus for Iran, and potentially for actors across North Africa and the Levant.
Beyond the F-35: Turkey’s Other Fighter Options
If the deal falls through, Ankara isn’t without alternatives — though none are as capable or immediately available as the F-35.
The KAAN Program
Turkey’s most ambitious alternative is the TF-X KAAN, an indigenous 5th-generation stealth fighter developed by Turkish Aerospace Industries (TAI) in partnership with BAE Systems. The KAAN completed its maiden flight in February 2023, a milestone that demonstrated real progress. However, the program faces significant challenges: Turkey currently lacks a domestic engine capable of powering the aircraft to its full design specifications, and the timeline to a fully operational, combat-ready fleet extends well into the 2030s. KAAN is a long-term solution, not a near-term answer.
The Eurofighter Option
Turkey has also expressed interest in acquiring Eurofighter Typhoons. While a capable 4th-generation-plus aircraft, the Eurofighter consortium involves the UK, Germany, Spain, and Italy — and Germany in particular has been reluctant to approve the sale given Turkey’s complex foreign policy record. The Eurofighter would bridge Turkey’s immediate capability gap but wouldn’t provide the stealth and networked capabilities of the F-35.
F-16 Upgrades
In the interim, Turkey has been upgrading its existing F-16 fleet and sought additional F-16 purchases from the U.S. — a deal that was eventually approved by Congress in 2024 after considerable political negotiation. F-16 upgrades provide near-term capability without resolving the longer-term modernization question.
Conclusion: A Pivotal Moment With No Easy Answers
The question of Turkey’s F-35 return sits at the intersection of military technology, alliance politics, and great power competition. Getting the answer right requires balancing genuine security concerns about the S-400 with the strategic value of a fully integrated, modern Turkish air force within NATO.
The key takeaways are these: Turkey’s exclusion from the F-35 program created a capability gap and a diplomatic fracture that neither Washington nor Ankara has fully moved past. The S-400 poses a real, technically grounded threat to F-35 stealth technology — this isn’t bureaucratic stubbornness but a legitimate security concern. President Trump’s openness to revisiting the ban creates a political window, but congressional opposition and unresolved technical questions mean that window is narrow.
A deal that genuinely resolves the S-400 issue — through verified deactivation, sale, or removal — while restoring Turkey’s F-35 access would strengthen NATO in meaningful ways: militarily on its southern flank, diplomatically in signaling alliance cohesion, and geopolitically in reducing Russian leverage in Ankara. A deal that papers over the S-400 problem with political promises, however, risks compromising the very technology it’s supposed to celebrate.
The balance is delicate, the stakes are high, and the outcome will shape NATO airpower dynamics for decades. For a topic this complex, the details matter as much as the headlines.
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Frequently Asked Questions
Why was Turkey removed from the F-35 program?
Turkey was officially removed from the F-35 program in July 2019 after it proceeded with the purchase and delivery of Russia’s S-400 missile defense system. The U.S. and NATO determined that operating both systems together posed an unacceptable security risk, as the S-400’s radar could potentially gather intelligence on the F-35’s stealth signature and transmit it to Russia.
What are CAATSA sanctions and how did they affect Turkey?
CAATSA stands for the Countering America’s Adversaries Through Sanctions Act. In December 2020, the U.S. imposed CAATSA sanctions on Turkey’s Presidency of Defense Industries (SSB) for its purchase of the S-400. The sanctions restricted technology transfer and export licenses, making Turkey the first NATO member ever sanctioned under this law.
What would Turkey need to do to rejoin the F-35 program?
Turkey would need to credibly address the S-400 issue to the satisfaction of U.S. officials and Congress. Potential options include returning or destroying the systems, selling them to a third country, permanently deactivating them, or finding a verified technical solution that prevents data collection. Each option carries significant political and logistical challenges for Ankara.
What is Turkey’s KAAN fighter jet and could it replace the F-35?
The TF-X KAAN is Turkey’s indigenous 5th-generation stealth fighter, developed by Turkish Aerospace Industries. It completed its first flight in February 2023. While the program represents a significant achievement, KAAN still lacks a domestically produced engine and won’t be combat-ready until well into the 2030s, making it a long-term rather than immediate solution to Turkey’s airpower needs.
How would Turkey’s return to the F-35 program affect NATO?
A Turkish F-35 fleet would significantly strengthen NATO’s southern flank — covering the Eastern Mediterranean, Black Sea, and approaches to the Middle East. It would improve interoperability across the alliance, increase burden sharing of high-end air capabilities, and send a strong geopolitical signal of renewed Western alignment by reducing Russian military influence in Turkey.
Why do U.S. lawmakers oppose restoring Turkey’s F-35 access?
Congressional opposition stems from several concerns: the unresolved security risk of the S-400 system, a broader trust deficit in the U.S.-Turkey relationship, and worries about setting a precedent that other allies could exploit by purchasing Russian weapons while expecting to retain access to advanced Western technology. The opposition is bipartisan and reflects deep institutional skepticism rather than opposition to Turkey as an ally.