Here's what I don't understand: If the plane were hijacked, what was the motivation behind doing so? Normally, hijackers take control of a plane with a clear goal/motivation in mind... crash it into a building, release a list of demands, etc.
So, with no apparent communication with air traffic control, no list of demands, no clear motive... What were/are they doing?
I'm just pulling this out of my ass here, but as far as I know, there is no precedent for someone stealing a commercial airliner, landing it, then attempting to use it as a weapon in a separate terror attack on a separate date. What I'm getting at is: who's to say that hijackers couldn't steal the plane, switch off its transponders, deliberately avoid radar, land the sucker, refuel, outfit it with a bomb (or just a full tank of fuel), then crash it into the Petronas Towers?
The only question then is what happened/happens to the passengers? They could be deliberately killed in-flight by a flight maneuver, taken hostage after landing, etc.
I know the above scenario is 100% conjecture on my part, but I'm trying to figure out why someone would hijack a plane, then completely disappear. It is a thought I'd never really contemplated before... What if the plane was stolen, refueled, possibly weaponized (loaded with explosives), and re-deployed? Scary stuff. The scenario gets even scarier if a terrorist organization ever gets their hands on a nuclear weapon.