In the months before the Sept. 11 attacks, federal aviation officials reviewed dozens of intelligence reports that warned about Osama bin Laden and Al Qaeda, some of which specifically discussed airline hijackings and suicide operations, according to a previously undisclosed report from the 9/11 commission.
The Bush administration has blocked the public release of the full, classified version of the report for more than five months, officials said, much to the frustration of former commission members who say it provides a critical understanding of the failures of the civil aviation system.
Among other things, the report says that leaders of the F.A.A. received 52 intelligence reports from their security branch that mentioned Mr. bin Laden or Al Qaeda from April to Sept. 10, 2001. That represented half of all the intelligence summaries in that time. Five of the intelligence reports specifically mentioned Al Qaeda's training or capability to conduct hijackings, the report said. Two mentioned suicide operations, although not connected to aviation, the report said.
Aviation officials amassed so much information about the growing threat posed by terrorists that they conducted classified briefings in mid-2001 for security officials at 19 of the nation's busiest airports to warn of the threat posed in particular by Mr. bin Laden, the report said.
Jane F. Garvey, the F.A.A. administrator at the time, told the commission "that she was aware of the heightened threat during the summer of 2001," the report said. But several other senior agency officials "were basically unaware of the threat," as were senior airline operations officials and veteran pilots, the report said.