Claim vs. Fact: Rice's Q&A Testimony Before the 9/11 Commission - Center for American Progress:
"Planes as Weapons

CLAIM: 'I do not remember any reports to us, a kind of strategic warning, that planes might be used as weapons.' [responding to Kean]

FACT: Condoleezza Rice was the top National Security official with President Bush at the July 2001 G-8 summit in Genoa. There, 'U.S. officials were warned that Islamic terrorists might attempt to crash an airliner' into the summit, prompting officials to 'close the airspace over Genoa and station antiaircraft guns at the city's airport.' [Sources: Los Angeles Times, 9/27/01; White House release, 7/22/01]…"

http://www.americanprogress.org/site/pp.asp?c=biJRJ8OVF&b=44918