He stated that within 24 ~ 48 hrs there would be some sort of announcement saying such.
This has always been the most plausible explanation to me.
If the plane had exploded in mid air, satellites would have seen it. If a plane that large had crashed in the ocean a multitude of stuff that does not sink would have been spotted with all the eyes in that area.
I would be disappointed with our current administration if they were to be honest with the public.
If it successfully ditched, it would just sink without a trace. But then you'd have to assume that all of the passengers were already dead.