U.S. President Donald Trump is expected to tell Turkish ​President Recep Tayyip Erdogan ​that he is prepared to allow the country ​to rejoin the F-35 stealth fighter program, the New York Times reported on Monday, citing four senior administration officials.The report comes as Trump heads ‌to Ankara ⁠for a ⁠NATO summit, where he is expected to meet Erdogan. The summit is ​set to begin on Tuesday evening.Also read: NATO allies seek to win over Trump after Iran ire as US Prez heads to TurkeyAccording to the New York Times report, ​the officials differed on the details of how Trump would seek to work around congressional and legal restrictions, but suggested there ​could be an exchange of letters ⁠on the ‌subject between the two leaders.The White House did ​not immediately ​respond to Reuters' request for comment on the ⁠report.Turkey's 2019 acquisition of the Russian S-400 air defense system has soured ties with the United States and hampered congressional support for Ankara. In response, Washington imposed sanctions and removed Turkey from the F-35 fighter jet program.Congress also passed a law prohibiting any sales of F-35s to Turkey as long as Ankara remained in possession of ‌the S-400s, saying the Russian system poses a security risk to U.S.-made combat aircraft.Also read: Daddy issues? NATO's Rutte sticks to charm to keep Trump on sideThe issue has remained ​a major ​point of contention ⁠between the two countries even though Turkey enjoys warmer ties with Washington under Trump.The reported development is a sign of improving ties ​between the two countries, especially after Trump's administration formally notified Congress of its intention to sell dozens of jet engines worth more than $700 million to Turkey last month, according to a copy of the formal notification seen by Reuters.