Quite possible yes.
I don’t know much about planes but #21’s first scenario seems more likely than that second scenario.
Since jumbo jets can be used as weapons the plane has to be tracked down even if finding it is unlikely. Terrorism cannot be counted out.
Of course....it’s been proven all too horrifically that jumbo jets can indeed be used as gigantic, piloted cruise missiles.
So finding it, either at the bottom of the sea or in some obscure location, is definitely a top priority.