If they keep on the way they are going, they have more to fear from loyal Americans than they do from Osama. Maybe that's why they beefed up security!
But one must never forget that the Islamic A$$hat is often as eager to attack his friend as his enemy. Several of the 9/11 hijackers listed the US intervention in Kosovo as one of their motivations in attacking the US. We intervened in Kosovo to defend Muslim (Radicals, Expansionists, Terrorists, Nationalists, Poor Innocent Little Victims -- pick one). For our trouble on their behalf, we got airplanes driven into our skyscrapers.
Really? I didn't hear that. That would be significant. It means the hijackers' real beef is that Americans interacted of their own volition with Kosovar Moslems while standing on their feet instead of lying on their bellies.
The first attempt to bring down the WTC was in 1993, before the US intervention in Kosovo. It stands to reason that other "grievances" were more important--US support for Israel, US support for conservative Arab monarchies, the US interventions in Lebanon, the fiasco in Somalia, etc., along with their general hatred of "infidels" and "Crusaders."