Canada

This report explains F-35 have no remote control nor kill switch, but depend on US companies for maintenance and parts.

Source : https://interestingengineering.com/military/f35-kill-switch-reports-debunked

Even if an F-35 operator disconnected from the larger Joint Strike Fighter program’s supply chains can keep some number of its jets flying for a period of time through spares on hand and cannibalization, those aircraft would have extremely degraded capabilities.

Source : https://www.twz.com/air/you-dont-need-a-kill-switch-to-hobble-exported-f-35s

Nothing in the article backs up the headline claim. The closest it gets is their quoted expert saying that he worries about the US doing to the F-35 what they're doing to Ukraine. He's almost certainly referring to the fact that parts and software updates are produced by the US, who could choose to withhold them, just like they're withholding aid from Ukraine.

Every serious defence analyst has laughed at the idea that the F-35 has a secret killswitch. This would be the dumbest thing ever to include in an aircraft, because there is always the possibility that your enemies could find out about it.

Consider; if an F-35 kill switch did exist, any buyer of the craft could invest the resources required to go over every inch of circuit and line of code and find it, and then deactivate every US F-35. It would be more of a liability for them than it is for us. And, equally, our experts could simply patch around the killswitch on our planes. Nations like Canada and Germany are not lacking in technical expertise.

This bonkers notion seems mostly to be rooted in the broader fear that the F-35 is somehow "too advanced", an idea that largely springs from the diseased brain of Pierre Sprey (seriously, if you chase down every bad thing said about the F-35, odds are ridiculously high that Sprey said it first). Sprey also believed that the ideal design for a modern attack fighter has a machine gun, no missiles, no computers, and no radar.

I'm not joking, not even slightly. Pierre Sprey wanted the modern world to fight Russia with planes that had no radar.

There are valid concerns to be raised about the idea of adopting a craft whose supply chain is centred on the US. That's a discussion that NATO partners should be having. But this "killswitch" nonsense just derails that important discussion into paranoid conspiracy theorist nonsense rooted in the deranged ramblings of a self-aggrandizing madman.

Not a fan of speculation and we're likely to never see any official documentation, considering it's a military aircraft.

But I will say: If it is true, it's probably the dumbest thing you could do to an advanced fighter like this. Just imagine that you're in a conflict, then the enemy hacks your command and control systems and disables/hijacks all of your aircraft. Yeah, that's pretty dumb.

Even the Star Trek writers realized this sort of thing is a bad idea.

And be careful with Switzerland ammo. They forbade Ukrainians to use it because of war. Literally. "You can't use our ammunition during the war".

Does anyone know of a FOSS F-35 alternative?

I feel like a jet and it's systems would be relatively easy to hack. The weapons on the other hand, not so much. Just window those to a certain geographical system or refresh their systems when they connect to gps or something

I guess the flip side of this is that the Americans are (presumably) actively training our military on the detailed operation and capabilities of the F-35. Could come in useful if things get bad. It's one of those things that is mind-bending about the situation we are in

Beyond any "off switch", you need permission on every flight for the "on switch". Lockheed doesn't even give US military manuals, and so only Lockheed consultants can maintain/repair the planes.

Beyond that, it is a horrible plane that is horribly expensive. Low flight time. Everyone in the world who approved buying any, is primafacie corrupt traitor, and straight to jail.

This is why you don't buy US.

Boeing taking a page from the John Deere playbook....

My understanding is that there's some weird shenanigans going on with an encryption key or something of that ilk that has to be renewed daily from US servers for the aircraft to continue to function, but I'm not sure how reliable the source I got that from is. However, I wouldn't buy F-35s either, if I were a nation-state shopping for aircraft.