I’ve always thought the plane crashed into the ocean, but if I were a terrorist leader with aspirations to hijack an airliner, the very first thing I would have thought of is to plant a false trail of breadcrumbs to lead everyone to look elsewhere. And real terrorist leaders are probably smarter than me ;-)
The real terrorists are studying the search and figuring ways to mislead even farther next time.
Smart enough to realize that if they want a plane they can buy a plane and not have to deal with all the hassles of hijacking it.