People have asked about the feasibility of Israel building its own stealth fighter. Theyโre not quite at that point, but Washington would have a very hard time cutting Israel out of the F-35 program.
Israel actually makes a lot of the F35s parts, specifically its outer wings, complex parts of the chassis, and the helmet mounted display- not just for Israel but for the entire global fleet. Israel is heavily embedded in the F35 program and would be very difficult to remove.
If they *did* try to remove Israel from the program, then Israel would take its tooling and production for stealth fighter components, its ability to manufacture unique avionics, radars, and weapons, and its unique position in having used them in combat more than any other country, and go to a competitors program. Probably not Russian or Chinese, but likely South Korean or Japanese.
Theoretically Israel could build its own but it would take an enormous amount of effort, and Israel canโt make jet engines like that.