Reply #10: Funny how the hijackers clustered around a handful of flight schools,

[Minstrel Boy]

and the schools never called authorities, yet the authorities knew immediately where the hijackers had trained. (See above: a Huffman executive was intimidated four hours after the attack by FBI agents, and flight school records were seized before the next morning.)

But when Zacharias Moussaoui approached a flight school outside of the terrorists' normal circuit, the flight school called the FBI the next day, and head office did all it could to derail the investigation.