Josh Voorhees, for Slate:

“But the huge uncertainty about where the plane was headed, and why it apparently continued flying so long without working transponders, has raised theories among investigators that the aircraft may have been commandeered for a reason that appears unclear to U.S. authorities. Some of those theories have been laid out to national security officials and senior personnel from various U.S. agencies, according to one person familiar with the matter. At one briefing, according to this person, officials were told investigators are actively pursuing the notion that the plane was diverted “with the intention of using it later for another purpose.””

Absolutely terrifying.