Before 9/11 hijackers would just ask for ransom and land the plane. This was unheard of and nobody expected this.
To the public this was unheard of. There was actually a plot devised by the people who first attacked the WTC back in '93 called Operation Bojinka. The operation involved hijacking airplanes from Asia, and bombing them mid-flight over the ocean. The last part of the operation was to crash a plane into CIA headquarters. This operation also included killing the Pope. This plan was devised in 1995, by the same people who plotted the 1993 WTC attack. One man who was involved in the plot was actually arrested before the plot could be carried out, and his partner in the plot was Khalid Sheikh Mohammed, who was the #2 to Bin Laden. After KSM was apprehended for his role in the 9-11 attack, he told investigators that the 9-11 attack was a a version of the Bojinka attack:
Bojinka plot - Wikipedia
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Bush & Co. lying to the public about how they never envisioned an attack like this on the U.S. was false. It's especially insulting when you realize that Bush & Co. were exposed for hiding the fact that Bush got intelligence briefings literally stating Al-Qaeda's intention to strike the U.S. that summer, months before 9-11:
Bin Ladin Determined To Strike in US - Wikipedia
en.wikipedia.org