According to the column by a Scott McCabe, a former airline pilot, the whole exectuives flying on the night of 12/31/99 or 1/1/2000 is really just a gimmick.

"First, there is no real possibility of any airliners falling out of the sky at midnight on New Year's eve. As machines, they are totally independent of any big, ground-based computers that might go belly-up with the turn of the century. Even the most sophisticated computerized airplanes we currently fly have no idea what year it is. The currency of our navigational databases are predicated on date, but if they are out of date they continue to work. No other computer on the airplane knows what day it is (or isn't)."

He gives a fairly convincing argument. For the entire article, follow this link: http://www.biztravel.com/V4/bizTravel.cfm?sec=4&User=0&Page=01050400&Data=0&ta rget=_top&dest=0