>The US are trying to alter the deal
I don't understand why people claim that. Here are the actual facts/timeline:
Nov 2021: Switzerland agreed contract terms with the U.S. government for 36 F-35A and budgeted CHF 6.035 bn. Under U.S. FMS (Foreign military sales) rules, LOA (letter of offer) values are estimates and the buyer owes actual full cost, so this was not an enforceable CHF-fixed total.
May 2022: The Swiss Federal Audit Office warned of legal uncertainty around any fixed price, but the warning was ignored internally.
Sep 2022: Parliament authorized; LOA signed Sep 19, 2022.
Jun 2025: Switzerland announced the U.S. disputes a binding fixed price and sought a diplomatic solution. U.S. officials pointed to inflation/raw-material/energy costs that have changed.
Aug 2025: Switzerland announced it cannot legally enforce a fixed price and is estimating additional costs (+CHF 650 m–1.3 bn).