It was the only flight able to leave the USA and if my memory serves me correctly it was the day of 9/11 not eight days later.

wiki:
At least 13 relatives of Osama bin Laden, accompanied by bodyguards and associates, left the United States on a chartered flight with Ryan International Airlines (Ryan International Flight 441) eight days after the September 11, 2001, terrorist attacks, according to a passenger manifest released on July 21, 2004