My Theory: Elements of the US government hired 19 arab men to take part in some kind of training/mission/operation - in the same way the FBI hired
Emad Salem to take part in the 1993 WTC bombing. The FBI mislead Emad to believe he was taking part in a sting operation that was designed to thwart the bombings, but when Emad discovered that he had been intentionally mislead, he blew the whistle on the FBI, and said they knew the four men accused of the bombings - were going to try and blow up the WTC.
http://whatreallyhappened.com/IMAGES/wtc_bombing3.wmv (Note: notice how Dan Rather says the FBI were applauded for how quickly they apprehended the four suspects...much in the same way the government discovered the 19 identities of the supposed hijackers from 9/11 in less than a day)
http://select.nytimes.com/gst/abstract.html?res=F00617FE3A5C0C7B8EDDA90994DB494D81
There have been reports of a connection between a Pakistani ISI (CIA) chief (General Mahumd) being directly involved in the wiring of $100,000 to Mohammad Atta (lead hijacker)
http://timesofindia.indiatimes.com/cms.dll/html/uncomp/articleshow?xml=0&art_id=1454238160
On Sept. 11, 2001, this ISI chief General Mahumd was in Washington meeting with US congress members and he also met with Colin Powell, Secretary of State.
Mysterious September 11 Breakfast Meeting on Capitol Hill.
"This meeting was described by one press report as a 'follow-up meeting' to that held in Pakistan in late August." Neither the Congressional 9-11 inquiry or the 9-11 Commission would touch this money trail from the ISI with a ten-foot pole.
So, the US government hired these 19 men to participate in some type of training/mission/operation - (the US probably mislead them about the exact intent of the operation much in the same way they lied to
Emad Salem about his role in the 1993 bombings) They had these 19 men train at various US flight schools in order to create a compelling back
story that meshed with the official
story. The 19 men probably had no idea of the elaborate plot they were taking part in.
On 9/11 - I believe the US government simply took drone aircrafts (a la ONW) and flew them into the twin towers. I think the reason they used drone aircraft was not to save the lives of the people on board the flights, but because they couldn't find pilots who would fly the planes into buildings.
Since, the government were the ones who hired these 19 men (just like 1993 bombings) they obviously knew everything about them, so that's how they "discovered," the identities of the "hijackers" in less than a day.