All aircraft were not grounded. A lot of Saudie and other middle eastern 'princes' and other lessers were flown out of Boston. Some relatives of Bin Ladin also.
Also, I think, Pres. Bush sent a plane to Australia to pick up Bill Clinton?
Yes, in Boston.
In the SF Bay Area, with its three busy international airports (SFO, OAK, SJO), it was very, very quiet.