If it is unable to purchase F-16 fighters from the US, Ankara would consider purchasing Russian Su-35 aircraft, according to Ismail Demir, President of the Turkish Defense Industry Bureau (SSB).

If buying F-16 fighters is not an option, Turkey has other possibilities. According to Demir, all possibilities have been discussed, including the Su-35 fighter.
A supersonic aircraft with exceptional manoeuvrability, the Su-35 can strike targets on land, at sea, and in the air, including air defence facilities.
After the United States pulled Turkey from its F-35 export programme in 2019, Turkey has continued to work on modernising the nation’s air force. Because Ankara won’t agree to terminate the agreement to purchase the S-400 air defence missile system from Russia, Washington declined to ship the ordered planes. Turkey at the time sharply chastised Washington, stressing that it was free to purchase arms from any nation it chose.
The purchase of 40 F-16 fighter jets, an outdated and less sophisticated variant of the Russian F-35, was then discussed by Turkey. The talks were “moving in a constructive path,” President Recep Tayyip Erdogan told reporters on September 22 in New York.
“We anticipate that the atmosphere will be upbeat. I believe the results will be available as soon as possible,” Erdogan stated.
US President Joe Biden declared in June that he wholeheartedly supported the sale of F-16 fighters to Turkey.