De Martini, construction manager, says in an interview that the WTC Twin Towers were designed to withstand MULTIPLE crashes of jet airliners. This is in February 2001 on the History Channel.

Unfortunately he died on 9/11. His offices were on the 88th floor of the North Tower. He helped more than 50 people escape before he perished.

Video is from:

http:/ /www(dot)youtube(dot)com/watch?v=bDGInaB0eQM