The relationship between the United States and Turkey remains complex, particularly regarding Turkey's involvement in the F-35 program. Turkey was expelled from the program in 2019 after opting to purchase Russia's S-400 air defense system despite warnings from the U.S.
Reports have surfaced suggesting that Turkey might consider relinquishing its Russian S-400s to rejoin the F-35 program, although these reports have been denied. The S-400 system has remained largely unused by Turkey, apart from initial testing.
Turkey has historically cooperated with the U.S., hosting the Incirlik Air Base where numerous B61 nuclear bombs are stationed. However, disagreements arose around 2016 over which advanced air defense systems Turkey should acquire. During this period, when Turkey felt vulnerable amid regional conflicts, it sought NATO's assistance for air defense support. The U.S., Spain, and Germany temporarily deployed Patriot batteries in response.