From the History Commons Groups blog:

A large number of entries have been added to the Complete 9/11 Timeline at History Commons, including many that provide new details about the events of September 11, 2001, and some that describe the initial official accounts of the military's response to the 9/11 attacks.

Air Force Secretary and Chief and Chief of Staff Learned of Attacks during Meetings

Several new timeline entries detail the actions of James Roche, the secretary of the Air Force, and John Jumper, the Air Force chief of staff, on September 11. Roche was alerted to the first plane crash at the World Trade Center during a meeting with several congressmen in his office at the Pentagon, in which the subject of Islamic fundamentalism was being discussed. Jumper, meanwhile, learned about the crashes at the WTC during a routine staff meeting, but he continued the meeting instead of responding right away.

After Jumper headed upstairs to Roche's office, the two men were escorted to the Air Force Operations Center in the basement of the Pentagon shortly after the building was attacked, at 9:37 a.m. When they arrived at the Operations Center, they started assisting the Air Force's response to the attacks.