US President Donald Trump's team has ordered the termination of vital support for F-16 fighter jet jamming equipment that Ukraine has. What is important to understand is that this could deprive the Ukrainian Air Force of its most important air countermeasures.
It’s certainly classified info, but I sincerely doubt the F35 has a kill switch.
If you have a kill switch on a weapon, that means an enemy can potentially disable your weapons.
One can argue that only export models would be equipped with a kill switch, but that puts the US in the position of potentially having Allied planes disabled remotely, leaving the US as the only air support in a conflict.
It’s far more likely that the US would simply discontinue parts and software updates, leaving a former ally scrambling to maintain their sudden white elephant fleet, while the US updates their own software to better manage fighting an identical aircraft that they know the exact technical specs of.
It’s also worth remembering that a bunch of the electronics in the F35 were developed by BAE Systems. If we really got to the “trying to sabotage the planes sold to allies” stage, America’s F35 fleet would be fucked too.