“A contributor to the History Commons has obtained a 298-page document entitled Hijackers Timeline (Redacted) from the FBI, subsequent to a Freedom of Information Act request. The document was a major source of information for the 9/11 Commission's final report. Though the commission cited the timeline 52 times in its report, it failed to include some of the document's most important material.

The printed document is dated November 14, 2003, but appears to have been compiled in mid-October 2001 (the most recent date mentioned in it is October 22, 2001), when the FBI was just starting to understand the backgrounds of the hijackers, and it contains almost no information from the CIA, NSA, or other agencies. This raises questions as to why the 9/11 Commission relied so heavily on such an early draft for their information about the hijackers.”

More here:
http://www.cooperativeresearch.org/fbi911timeline
(Local mirror of zip file: 7.8 MB)

Summary of what the FBI document reveals: