Taking it a step further...why even use a jetliner?
If somebody wanted to deliver a nuke or even a lot of explosives, wouldn’t an ordinary run of the mill private airplane do the trick? They could just steal one from the local air strip hangar and skip the whole hijacking a jetliner step.
Whatever the government knows it most likely wouldn’t be telling us. For many reasons, the government lies.
Well, what if the passengers were kept safe so that they could be boarded again. At that point, let them make all the cell phone calls they want so they can let everybody know they are still alive and coming home. Load the 777 with a nuke and tell the world they will be freed when they land in Israel. The moral dilemma might buy enough time to get into Israeli air space and ..... welll... let’s hope I’m wrong.
Or a cargo container--we don't search all of them, AFAIK. A nuke-carrying cargo container in a port with a major amount of LNG storage would create a spectacular disaster.