which is a game played by historical revisionists, conspiracy mongers, and fools. You seem to fit all three categories.

You have to look at what was known about the situation AT THE TIME, not what is known now.

So, what was known at the time?

1. The FAA knew a plane was being hijacked within a few minutes of the takeover. Did they know it was going to be flown into a building? No. Did they know it was any different from any previous hijacking? No.

2. Soon afterwards, a second plane was hijacked. By the time they realized what was going on, it was too late to stop either one of them.

3. Within minutes, a third and fourth airliner was hijacked.

4. Now, they had over 4000 planes in the air with an unknown number of possible threats. It turned out that 4 airliners were hijacked from two different airports within a very short time span. This had never happened before. They had no way of knowing if other planes were also about to be hijacked or how many of them were threatened. They were ordered to ground all flights across the United States, something that had never happened before. There weren't even contingency plans for doing such a thing. So, while being on the alert for possible additional hijackings, they had to frantically issue new instructions to get all those 4000+ planes on the ground ASAP. Planes were forced to make unscheduled landings all over the country without the opportunity to do much in the way of planning. This made the problem of detecting other possible hijacked planes even more difficult.

The military only had about 14 planes on alert nationwide. They reacted as quickly as they could under the circumstances with fighter pilots facing the unprecedented prospect of having to shoot down airliners full of Americans over our own soil.

In the end, everyone involved did the best job they could given what was known at the time. For some asshole like you to come along a year later with dumbass conspiracy theories like the drivel you've been spouting is worst than an insult to all involved. You should be ashamed of yourself for being so stupid as to believe this nonsense.