Did you know there were other would-be hijackers that planned to take over flights on 9/11 but could not complete their mission because their planes were grounded.

This History Chanel program discusses how a flight was grounded and the would-be hijackers fled the plane. Authorities found al-Qaeda material in their luggage.

http://www.thehistorychannel.co.uk/site/tv...gramme_2998.php

There were to be more than four hijacked planes on 9/11.

Interesting issue which was never explained.

See here for details:
http://11september-paxamericana.chez-alice...erebeenmore.htm