"Hi, you need to install this critical feature upgrade or your F35 may fly unstable paths and kill your pilot during combat"
...
"yea, we did disable 99% of the functionality, come back when the trade negotiations finish"
alternatively:
"we found problems. You can't have them until you agree to trade terms. PS they make for unstable flight. your pilots may day in combat"
alternatively:
"if you refuse to agree to our trade terms, then we refuse to tell you about critical subsystem diagnostics and your airframe may not be servicable"
&c &c &c.
I would not call any of these an in-flight kill switch. I would call all of them varying degrees of remote software control. albiet across maintenance functions.
"Hi, you need to install this critical feature upgrade or your F35 may fly unstable paths and kill your pilot during combat"
...
"yea, we did disable 99% of the functionality, come back when the trade negotiations finish"
alternatively:
"we found problems. You can't have them until you agree to trade terms. PS they make for unstable flight. your pilots may day in combat"
alternatively:
"if you refuse to agree to our trade terms, then we refuse to tell you about critical subsystem diagnostics and your airframe may not be servicable"
&c &c &c.
I would not call any of these an in-flight kill switch. I would call all of them varying degrees of remote software control. albiet across maintenance functions.
No magic back door required.
tl;dr: the US can’t remotely brick your airplanes, but it absolutely can brick your airplanes remotely… unless you happen to be Israel.