According to the "Fareologist" at Bing Travel, Microsoft's new travel search site, holiday air travel will be cheaper than last year.

Airfare for Thanksgiving travel around the U.S. will average $327, down 22% from last year. Christmas and New Year's holiday airfare will average $353, down 17%.

But of course with lower ticket prices, planes will be fuller, so it's wise to book your ticket now to avoid the dreaded middle seat. Another good reason to plan ahead: Air fares won't be decreasing as the holidays near.

Fareologist Joel Grus does recommend watching for holiday price drops in the first half of October. "Since 2006, most Christmas itineraries saw price drops in the first two weeks."

Still if you see a good fare for your specific days of travel, jump on the next good fare you see as fares typically increase as the holiday season gets closer.

However, if you're flexible with your travel dates, you can save a few bucks. Bing Travel data says returning the Monday after Thanksgiving instead of Sunday can can yield a savings of $35 per ticket. Christmas doesn't offer the same savings opportunities, but if you travel on Christmas Day, you'll save an average of $45 per ticket -- not including all the fees for checked and overweight luggage, of course.

For more Black Friday coverage, check out our Black Friday Deals and other Black Friday 2009 news today.