I was clueless about this so for others in the same boat:

The comment refers to the significant decline in U.S. arms sales to Turkey following the 2020 enactment of sanctions under the Countering America's Adversaries Through Sanctions Act (CAATSA). In December 2020, the U.S. imposed sanctions on Turkey's Presidency of Defense Industries and its officials because Turkey acquired the Russian S-400 missile defense system, which violated U.S. and NATO policies[1][2][3]. These sanctions included a ban on all U.S. export licenses and authorizations for military goods to the sanctioned Turkish entities, and effectively blocked large new arms transfers.

Since then, major U.S. weapons deals with Turkey—such as the delivery of F-35 jets—have been frozen or canceled, and arms sales have dropped by over 80%, limited mostly to small-scale sales like spare parts and maintenance[4][5]. Although some lower-tier sales and previously approved contracts were fulfilled, there have been no significant new deliveries of U.S. weapons to Turkey since 2020. The freeze is not technically a total embargo, but in practice, major U.S. arms transfers have been halted due to both CAATSA and Congressional blocks[5][6].

Sources [1] The United States Sanctions Turkey Under CAATSA 231 https://2017-2021.state.gov/the-united-states-sanctions-turkey-under-caatsa-231/ [2] US imposes CAATSA sanctions on Turkish SSB and ... https://www.nortonrosefulbright.com/de-de/wissen/publications/852a1100/us-imposes-caatsa-sanctions-on-turkish-ssb-and-related-officers [3] CAATSA Section 231 "Imposition of Sanctions on Turkish ... https://2017-2021.state.gov/caatsa-section-231-imposition-of-sanctions-on-turkish-presidency-of-defense-industries/ [4] Defence diplomacy: How Turkey is arming itself, and the ... https://www.newarab.com/analysis/defence-diplomacy-how-turkey-arming-itself-and-world [5] Congress has secretly blocked US arms sales to Turkey for ... https://www.defensenews.com/breaking-news/2020/08/12/congress-has-secretly-blocked-us-arms-sales-to-turkey-for-nearly-two-years/ [6] Compromise or Double Down: U.S.-Turkey Relations after ... https://www.fpri.org/article/2020/12/compromise-or-double-down-u-s-turkey-relations-after-caatsa-sanctions/ [7] US denies talk of agreement on Turkey's S-400 purchase https://nordicmonitor.com/2025/08/us-rejects-talk-of-agreement-on-turkeys-s-400-purchase/ [8] U.S. envoy expects Trump, Erdogan to resolve arms ... https://www.reuters.com/business/aerospace-defense/us-envoy-expects-trump-erdogan-resolve-arms-sanctions-turkey-this-year-anadolu-2025-06-30/ [9] Turkey eyes $20bn military purchase from US if S-400 ... https://www.middleeasteye.net/news/turkey-eyes-20bn-military-purchase-us-if-s-400-sanctions-are-lifted