At least 83 flights operated by U.S.-sanctioned Iranian airlines landed in Turkey in the five days after a key American sanctions deadline, according to flight data analyzed by the Foundation for Defense of Democracies, putting a new spotlight on whether Washington will enforce its escalating pressure campaign against companies servicing the carriers in a NATO ally.

The Sept. 28 FDD report said U.S. pressure has helped push Iranian airlines out of several regional markets, including Iraq, the United Arab Emirates and Oman, but found that Turkey remains a significant gap in Washington’s effort to ground the carriers.

The findings come after the Treasury Department announced sweeping new sanctions on Iran’s aviation industry on Sept. 8, designating all 27 remaining active Iranian airlines under Executive Order 13902. Treasury said Iran's aviation sector has been used to transport weapons, personnel and illicit cargo and warned foreign businesses about the risks of continuing to support sanctioned carriers.

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The continued Iranian flights come at a sensitive moment in U.S.-Turkey relations. Turkey is a NATO ally, and President Donald Trump has publicly emphasized his close relationship with Turkish President Recep Tayyip Erdoğan while signaling openness to restoring Ankara’s access to the F-35 fighter jet program. Turkey was removed from the program after purchasing Russia’s S-400 air-defense system, a move that also triggered U.S. sanctions in 2020.

During a July 2026 visit to Turkey, Trump said his administration would lift those sanctions and was considering allowing Ankara to buy F-35s, though congressional restrictions tied to Turkey’s possession of the S-400 remain an obstacle. Erdoğan said as recently as Sept. 24 that he expects Washington to take "concrete steps" toward Turkey’s return to the program.

Treasury Secretary Scott Bessent warned that after a Sept. 23 wind-down deadline, companies providing sanctioned Iranian airlines with services such as fuel or landing support risked losing access to the U.S. financial system. FDD cited Bessent saying that by that date, Iranian airlines would be "shut down around the world."

But FDD researchers Ahmad Sharawi and Sinan Ciddi said their review of Flightradar24 flight histories showed that at least 83 flights operated by U.S.-sanctioned Iranian carriers landed in Turkey between Sept. 23 and Sept. 27, after that deadline had passed. The flights landed in Istanbul, Ankara and Izmir, according to the report.

The researchers identified 12 sanctioned Iranian airlines among the arrivals. Iran Airtour and Caspian Airlines each accounted for 12 landings, Iran Air for 10, and ATA Airlines and AVA Airlines for nine each, according to FDD. Eight of the 12 carriers identified in the flight data were among the airlines newly designated by Treasury on Sept. 8.

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The Treasury Department told Fox News Digital that it has continued raising the issue directly with senior Turkish officials and has warned Turkish companies and financial institutions about their potential sanctions exposure.

"Following Treasury’s productive engagements with senior Turkish authorities last month, which quickly translated into tangible results — including the cancellation of Mahan Air flights and the revocation of Bank Mellat’s license — we have continued discussions regarding Türkiye’s aviation links to Iran and the sanctions exposure Turkish financial institutions and businesses face for facilitating these flights," a Treasury spokesperson told Fox News Digital. "We have made those risks clear and continue to address these issues at senior levels with the Turkish government," the spokesperson said.

The Treasury spokesperson pointed to the administration’s broader "Operation Economic Outcast" campaign, saying it was producing results as Washington seeks to cut off Iran’s remaining sources of revenue and access to international markets. "Operation Economic Outcast is delivering results as Treasury and our partners continue to sever the Iranian regime’s remaining economic lifelines," the spokesperson said. "Iran’s rial has fallen to record lows, Iran loaded no crude oil onto tankers in September, and countries across the region are taking concrete steps to restrict Iran’s access to the international financial system and commercial aviation."

"We will continue applying pressure and holding accountable those who provide the regime with the financial and commercial lifelines it needs to sustain its terrorist activities," the spokesperson added.

Turkey has indeed taken some steps to limit aviation ties with Iran. Turkish Airlines, AJet and Pegasus removed flights to Iran from their schedules, while Mahan Air suspended service to Turkey beginning Sept. 21, according to Turkish Minute, citing airline schedules and reporting by the Financial Times and other outlets.

Mahan Air has been under U.S. sanctions since 2011. The Treasury Department said at the time that the airline provided financial, material and technological support to Iran’s Islamic Revolutionary Guard Corps-Quds Force.

Other sanctioned Iranian airlines, however, have continued flying into Turkey. Caspian Airlines and Meraj Air were designated by Treasury as Specially Designated Global Terrorists in August 2014. Treasury said Caspian had transported IRGC personnel and weapons to Syria and said Meraj had ferried illicit cargo, including weapons, to the Syrian government.

Sharawi told Fox News Digital that the continued flights reflect a gap between Ankara’s public steps and its handling of sanctioned Iranian carriers.

"The fact that sanctioned Iranian airlines continue to land in Turkey, despite Washington’s clear effort to restrict their operations, is a testament to Ankara’s willingness to take symbolic measures while turning a blind eye to much of Iran’s broader activity," Sharawi said.

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Sharawi argued that Washington could increase pressure by targeting Turkish companies that continue providing services to sanctioned Iranian carriers.

"Ankara may think it can get away with this, but Washington has not hesitated in the past to sanction Turkish entities that support sanctioned Iranian actors," he told Fox News Digital. "Continuing to target companies that provide that support would send a clear message to Ankara that facilitating Iran’s sanctioned networks will carry consequences."

He said such measures could have a practical effect on Iran’s ability to maintain the routes.

"If the United States targets the support system that keeps these sanctioned Iranian carriers operating, private Turkish companies will have much less incentive to continue doing business with them," Sharawi said. "If those companies begin cutting ties, it could significantly restrict Iranian airlines’ ability to operate routes to Turkey."

The Turkey findings come as another advocacy group is raising concerns about a different potential weak point in Washington’s campaign to isolate Tehran: Iranian maritime commerce in waters near Malaysia.

United Against Nuclear Iran said Sept. 25 that its investigators traveled roughly 100 nautical miles into the South China Sea near Malaysia’s Eastern Outer Port Limits, where the group said it observed Iranian-linked tankers, cargo vessels and bulk carriers alongside Malaysian bunker vessels supplying ships with fuel. UANI described the concentration of ships as a "floating city" supporting Iran’s sanctions-evasion network. Those findings were produced by UANI and have not been independently verified for this draft.

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"After seeing this floating city of ghost tankers with our own eyes, it is clear it is serving as an illicit Malaysia-backed lifeline for the Iranian regime," UANI CEO Ambassador Mark D. Wallace said in a Sept. 25 statement. He accused Malaysian entities of providing support that allows Tehran to continue generating revenue despite international efforts to economically isolate the regime.

Former Florida Gov. and UANI Chairman Jeb Bush and Wallace called on the Treasury Department to sanction entities associated with Malaysia’s Pengerang petroleum complex as well as Malaysian entities or officials they allege are facilitating the trade. Their call for sanctions is an advocacy position and does not establish that the Malaysian entities have violated U.S. law.

Fox News Digital has learned that Treasury has mapped Iranian oil-smuggling networks, facilitators and financial channels, including deceptive shipping activity off the coast of Malaysia, and that senior Treasury officials continue to raise the issue with Malaysian and other foreign government counterparts.

Taken together, the findings from FDD and UANI highlight what the organizations describe as continuing enforcement challenges as Washington attempts to cut Iran off from international aviation, shipping and financial networks. Treasury has continued expanding that campaign: on Sept. 29, it announced another round of sanctions targeting individuals and companies it said had procured weapons and components for Iran’s Ministry of Defense and Armed Forces Logistics.

Fox News Digital reached out to the Turkish and Malaysian embassies for comment but did not receive a response.