Having just started a new job, I haven't taken time for a 9/11 post, so I'll quickly point out a bit from Dean Barnett's:
To fully understand the threat that groups like Al Qaeda represents, you have to toss a couple of complexities into the mix. The first regards the abilities of Al Qaeda’s members. Al Qaeda’s troops, including their leaders like Zawahiri and bin Laden, almost uniformly lack military training. The best Al Qaeda “soldier” would last about three seconds with the typical American Army Ranger.