Terrorists tend to be stupid. Honestly. Look at Richard Reid, the shoe bomber. The guy goes to the airplane bathroom to prepare his shoe bomb, then he returns to his seat, covers himself with a blanket, and tries to detonate the bomb by lighting the fuse with matches. People next to him notice this easily and maul him. Plot over. So, ummm, why not just detonate the thing while locked in the bathroom??? The guys in flight school just got lucky for the most part, but you're right that it was a strange decision.

It's hard to find good help.

Yeah, I've always thought it was insane that for an operation as huge as 9/11 they'd do something as risky as train in the US itself. Rather than venture into conspiracy land (nothing against conspiracies in general; they're often entertaining and, depending on the subject and degree, are not necessarily invalid), I wondered if there were plausible explanations for it.

I can buy the idea that they either didn't think the possible risks through, or just believed they could get away with it long enough to pull off the attack. And also that they may have thought they could learn more about US aviation policy or protocol in the US than elsewhere.

I was sceptical about it being because there are more flight schools in the US, because AIUI they only acquired limited training anyway, which they could have received anywhere. But whatever competence and training they ended up with, they probably at least intended to get as much as possible, and train in bigger, more appropriate aircraft, so that is possibly a factor too.

Thanks everyone for the replies.

When you only have a small explosive, you want to detonate it as close to the wing as possible, as this is the weakest spot on the plane - you're basically hoping for the wing to fall off, or at least sever the connections to the control surfaces. Even with a decent hole in the fuselage, there is a very good chance of landing the plane safely as long as the wings stay on.

https://en.m.wikipedia.org/wiki/Aloha_Airlines_Flight_243

To be clear, the wingbox is, by far, the strongest part of a plane, but it's the most devastating if you can compromise it. (And its primary design goal isn't to account for explosive loads coming from the fuse.)

You aren't going to compromise the wingbox with an explosive that fits in the heel of a shoe.

Most flight training in the world is done in the US, by a wide margin.

Because of that, they would probably stick out much less doing it here than trying to do it in one of the few EU airline training facilities.

Not only that, but for the plot to work, the hijackers had to start from within the US. Implanting them in the US long before the attacks made it easier for them to reliably get to their target airports the day of the attack.

In a sense, the comment upthread litigates the whole idea of a "sleeper cell."

Is that the right word? Validates? mitigates?

Purposefully argue or debate a position, seeking its resolution, as if before a tribunal.

It's cheaper in the US than pretty much anywhere else, and there are large numbers becoming pilots, so more noise to hide in. It might be cheaper to train is some weird and wonderful corners of the world, but they'd have been far more noticeable.

I would venture that the hijackers were just really bad at counter espionage?

You had organizations that had the signals but couldn't communicate, why is it anymore likely that the terrorists themselves were super geniuses?

>Has there ever been an explanation why the hijackers risked conspicuously attending flight schools under the noses of the US authorities, rather than, say, absolutely any other country in the world?

Because there are more flight schools in the US than anywhere else, and if you want to do some flying in US airspace, those are in the best position to teach how it works, what controls there are, how to avoid them, etc.

The better to learn how US airspace worked?