Clever, indeed, but people learn and adapt.
The reality of it however, is that there are far more Atta's out there than McVeigh's, and they are constantly plotting to KILL American's and destroy the American way of life (did you hear that Joe?). The troubling thing is that they are very smart, clever and know that we are looking for the above descriptions - hence, they may be walking among us and we don't even know it.
The fact that the only real "weapons" needed for 9/11 was a couple of box-cutters and out past experience with plane hijackings.
In the past, hijackings meant an inconvenience for passengers, nothing more. The hijackers would get a ride to their destination, the plane would be released, and the passengers would be returned safely, albeit a bit worse for wear.
What nobody counted on was that these guys were willing to die for their cause and take as many innocents as needed to accomplish their plan! Never did it occur to the passengers that they were riding in a missile that would be deployed at buildings, using jet fuel as the explosive.
Once the first few succeeded in their plan, the element of surprise was over. Flight 93 got wind of what was going on and, true to the true American spirit, rather than go down like meek, cowering wimps knowing they would be the instrument of death of even more innocents, a few fought the hijackers and took their destiny in their own hands and denied them their victory.
To this day, I don't think anyone will simply "assume" a hijacking will be only a temporary delay to their destination and woe be to anyone who tries it.
We live and learn. Fool me once, shame on you. Fool me twice, shame on me.
