As President Recep Tayyip Erdoğan and U.S. President Donald Trump are expected to meet in New York during the week of the 81st United Nations General Assembly, defense ties between the two countries will be one of the most closely watched areas of the meeting.
The exact date, time and detailed agenda of the meeting have not yet been made public. However, there is keen interest in whether the leaders will deliver new messages on the long-standing F-35, F-16, S-400 and CAATSA issues between Türkiye and the United States.
The S-400 is at the center of the F-35 dispute
Türkiye was one of the original partners in the F-35 fighter jet program.
However, after Ankara purchased the S-400 air defense system from Russia, Washington began the process of ending Türkiye's participation in the F-35 program.
The U.S. administration argued that the S-400 system was incompatible with the security of F-35 technology. Türkiye, meanwhile, has long called for a resolution to the problem surrounding the F-35 program.
For this reason, close attention will be paid to whether the Erdoğan–Trump meeting produces a statement pointing to a new political or diplomatic process on the F-35 issue.

CAATSA sanctions remain a key issue
Another consequence of the S-400 purchase was the U.S. imposition of sanctions on Türkiye's Presidency of Defense Industries under CAATSA.
The U.S. State Department had said that the sanctions were imposed because Türkiye purchased the S-400 system.
The CAATSA issue remains one of the key areas of difficulty in defense industry ties between Türkiye and the United States.
For this reason, close attention will be paid to whether the leaders' meeting in New York produces any message about the future of the sanctions.
The F-16 track followed a different course
Separate from the F-35 crisis, Türkiye pursued a lengthy process with the United States on modernizing its existing F-16 fleet and procuring new aircraft.
In previous years, the Washington administration had said that modernizing Türkiye's F-16 fleet was important for NATO interoperability.
For this reason, the New York contacts will focus not only on the F-35 issue but also on the modernization of Türkiye's air force and the future of broader defense cooperation between the two NATO allies.

Will the meeting signal a new phase in defense ties?
One of the main points to watch in the defense dimension of the Erdoğan–Trump meeting will be whether the two leaders put forward a new mechanism or demonstrate the political will to resolve the existing problems.
For Türkiye, the F-35 and CAATSA files remain important, while for Washington the S-400 issue has long been one of the main points of disagreement.
In addition, NATO, regional security, Syria and cooperation in the defense industry form the broader framework of the two countries' security relationship.
Attention turns to statements from New York
Since the detailed agenda of the Erdoğan–Trump meeting has not been announced, it is not yet known which of the F-35, F-16 or CAATSA issues will be directly discussed.
However, the language used on defense ties in statements by the Presidency of the Republic of Türkiye and the United States after the meeting could offer important clues as to whether a new phase is beginning in the Ankara–Washington relationship.
For this reason, close attention will be paid in New York not only to regional crises but also to messages about the future of defense ties between Türkiye and the United States.