The preliminary report by the National Commission on Terrorist Attacks Upon the United States said that in a presentation to airline and airport officials in early 2001, the FAA discounted the threat of a suicide hijacking because there was "no indication that any group is currently thinking in that direction."
In July 2001, the FAA issued a warning to air carriers but did not mention suicide hijackings. Instead, it focused on the possibility that some terrorist groups might conceal explosive devices inside luggage.
Bush administration officials have maintained that before the attacks there was no indication terrorists were considering suicide hijackings. But the report said the FAA's Office of Civil Aviation Security officially considered the possibility of suicide hijackings as early as March 1998.
The report, released Tuesday, acknowledged there was no specific intelligence indicating suicide hijackings would occur but said the FAA still had a responsibility to protect the flying public against such a threat.
"Without actionable intelligence information, to uncover and interdict a terrorist plot in the planning stages ... it was up to the other layers of aviation security to counter the threat," the report said.
The 10-member, bipartisan commission was established by Congress to study the nation's preparedness before Sept. 11 and its response to the attacks, and to make recommendations for guarding against similar disasters.
On Monday, the first day of a two-day public hearing, the commission said U.S. authorities missed some obvious signs that might have prevented some of the Sept. 11 hijackers from entering the country.
Government officials have said the 19 hijackers entered the country legally, but the panel said its investigation found at least two and as many as eight had fraudulent visas. The commission also found examples in which U.S. officials had contact with the hijackers but failed to adequately investigate suspicious behavior.
For example, Saeed al Ghamdi was referred to immigration inspection officials in June 2001 after he didn't provide an address on his customs form and had only a one-way plane ticket and about $500. Al Ghamdi was able to persuade the inspector that he was a tourist.
The panel also found that at least six of the hijackers violated immigration laws by overstaying their visas or failing to attend the English language school for which their visas were issued.
And Khalid Sheikh Mohammed, believed to be the mastermind of the Sept. 11 attacks, exploited the fact that customs officers did not routinely collect fingerprints to obtain a visa, even though federal authorities in New York indicted him in 1996 for his role in earlier terrorist plots. He never entered the country and was apprehended after the attacks.
The commission said part of the problem was a lack of coordination among immigration officials and a focus on keeping out illegal immigrants rather than keeping out potential terrorists.
The commission detailed other government missteps prior to September 2001:
Also Monday, the commission said it can't finish its final report by the May 27 deadline imposed by Congress and asked for an extension of at least two months. The Bush administration and Republican congressional leaders have said they oppose such a move.
Commissioners decided they needed more time because the group had been bogged down by disputes with the administration and New York City authorities over access to documents and witnesses, according to a person familiar with the commission who spoke on condition of anonymity.