I mean, it doesn’t mean we couldn’t, just that it was not worth revealing our ability to do so over one airliner crash where no one was likely to survive. They didn’t directly act on intelligence in enigma for the same reason either if memory serves. Tin foil hats are itchy…

If your argument is "MH370", it's a weak one. No one has radar coverage in the southern Indian Ocean because no one needs it.

There was an article about that very topic on HN just recently. It was not even remotely over US airspace, and the pilot had evidently threaded the needle through the radar coverage of several nations.

Umm, NORAD is able to track Santa - this balloon is much easier.