IIRC, it was off the NE seaboard, the pilot left the cockpit for a moment, the co-pilot took the controls and pitched the plane violently up and down, the pilot made it back and asked "What are you doing?!" and the co-pilot was praying.
Again, IIRC, the plane was deliberately plunged nose-first in the Atlantic.
I'm thinking it might be something similar here, or a bomb.
Bojinka also comes to mind.
The Air France jetliner off the Brazilian coast comes to mind.
There was a plot to use an airliner to strike the Eiffel Tower, which the French averted. Again, a common thread (or "threat") is that Muslim actors were involved.
I'm about ready to advocate that we just isolate these cavemen for 500 years. Hell, after the first fifty they wouldn't be able to produce radio, TV, aircraft, and would just sink back down to the level of stone knives and bearskins.
they’ve already got terrible inbreeding problems from 1400 years of marrying too-close relatives to preserve wealth in the families.