If the plane is stolen for a future attack they have unnecessarily taken too much of trouble - First plan a theft which is incredibly difficult that hijacking a

If the plane is stolen for a future attack they have unnecessarily taken too much of trouble - First plan a theft which is incredibly difficult that hijacking and then ramming it somewhere - Then actually keep it hidden while half the world is searching for it. - Get rid of those passengers - Hiding a Boeing 777 is not same as hiding a cookie jar. The plane will need a runway, fuel etc. which needs to be provided for and can be easily tracked. - Terrorism is all about surprise. There is no surprise involved here. All the countries will now be much more cautious with any object that appears on their radar.