http : //en.wikipedia.org/wiki/mohamed_atta a plausible alternate theory identified identity theft : http : //www.aldeilis.net/english/index.php ? option=com_content & view=article & id=3188 : the-atta-mystery-double-agent-or-multiple-attas [ 130 ] a panel of experts assessed the best evidence for the hijackers at dulles airport and concluded that there was no evidence for hijackers arriving for flight 77. http : //www.consensus911.org/point-video-2/ [ 131 ] in summer 1999 , a teenager was able to climb over the airports security fence , walk two miles across the tarmac , board a 747 , and fly on to london .