Note: this is basically a re-hash of the rather unwieldly (but information-packed) post at http://seattle.indymedia.org/front.php3?article_id=14805&group=webcast
What I'd like to know is who else was at that supposed charity event. Can anyone help?
1) Who was at Offutt Airforce Base, home of the U.S. Strategic Command, Sept. 11?
-- George W. Bush and a "group of business leaders", which is quite a coincidence seeing
how the base is located in out-of-the-way Nebraska. Among the business leaders:
Warren Buffet, second richest man in America [1, 2] and
Anne Tatlock of Fiduciary Trust Co. International, which was bought by mutual fund firm
Franklin-Templeton five months before the attacks (Fiduciary's offices were on floors 92-97
of the WTC's south tower). 
2) When was this?
-- Ms. Tatlock, in order to have witnessed the the first plane hitting the north tower, would
have had to have been there as early as 8:00 a.m. CST. President Bush left Barksdale Air
Force Base for Nebraska's Offutt Air Force Base at 1:44 p.m. At 4:30 p.m., he left Offutt aboard
Air Force One to return to Washington. 
3) Why were they there?
"By the afternoon of September 12, the Associated Press and Reuters were carrying stories,
widely circulated throughout the media, that were intended to diffuse criticism of Bush's actions
the previous day. They quoted a White House spokesperson saying, 'There was real and credible
information that the White House and Air Force One were targets of terrorist attacks and that the
plane that hit the Pentagon was headed for the White House.' White House Press Secretary Ari
Fleischer repeated this claim at an afternoon news briefing that same day, saying the Secret Service
had 'specific and credible information' that the White House and Air Force One were potential targets.
"In a further column in the New York Times on September 13, entitled 'Inside the Bunker,' Safire described
a conversation with an unnamed 'high White House official,' who told him, 'A threatening message received
by the Secret Service was relayed to the agents with the president that "Air Force One is next." ' Safire
continued: 'According to the high official, American code words were used showing a knowledge of
procedures that made the threat credible.'
"Safire reported that this information was confirmed by Rove, who told him Bush had wanted to return
to Washington but the Secret Service 'informed him that the threat contained language that was evidence
that the terrorists had knowledge of his procedures and whereabouts.'" 
"The president was told he could get to Offutt Air Force Base in Nebraska more quickly than to Washington,
thus allowing him to conduct the national security meeting at a secure location and address the public
for a second time." 
This explanation was later dropped by the mainstream press. 
-- Business leaders:
All Ms. Tatlock says in the sourced article is that it was "for a charity event hosted by Warren Buffett."
 "Warren Buffett warns on terror risk" http://news.bbc.co.uk/hi/english/business/newsid_1970000/1970409.stm
Sample quote: "We're going to have something of a major nuclear event in this country,"
Mr Buffet said following the annual general meeting of his company Berkshire Hathaway.
 "Franklin unit rebuilds after 9/11 tragedy" by Ron Leuty, San Francisco Times, print edition Feb 1, 2002
Sample quote: "On the morning of Sept. 11, Tatlock herself had just arrived with a small group of
business leaders at Offutt Air Force Base in Omaha for a charity event hosted by Warren Buffett.
She then heard the news of the first plane hitting the World Trade Center's north tower."
 The Home Front by Gary North: "White House Shoots Down Air Force One Story" http://188.8.131.52/search?q=cache:j3fTpyW545gC:www.lewrockwell.com/north/north60.html+offutt+corporate+meeting+bush+September&hl=en&ie=UTF
 Associated Press article reprinted in the Sept. 13 issue of New Hampshire's Foster's Daily Democrat. Quoted in above source (4).
Also see "9/11 absentees, the WTC CEO survivors" at http://www.indymedia.org/front.php3?article_id=182245