From Sam Lee, who works at Hotwire.com:

2004 Fall / Winter Holidays: Best days to fly

Cheapest time to fly:

"Shoulder periods" before, between and after the major holidays:
Nov 1-19
Nov 30 - Dec 16
January 4 or later

If you must fly around the holidays...

Best bets:

Nov 20-23
Thursday, Nov 25 (Thanksgiving Day)
Saturday, Nov 27
Monday, Nov 29
Dec 17
Dec 24 &25 (Christmas Eve & Day)
Dec 29
Dec 31 & Jan 1(New Year's Eve & New Year's Day)
Jan 3

Avoid:

Wednesday, Nov 24
Friday, Nov 26
Sunday, Nov 28
Dec 18-23
Dec 26-28
Dec 30
Jan 2