Is there a predictable cycle to airfares?

I am shopping around for a vacation around Thanksgiving, and over the last few days I’ve noticed what seem to be significant swings in the prices over the last week.

The fares started out early this week at what I’d call a reasonable number. By Wednesday, prices dropped a little bit – I’ve heard that low fares tend to come out mid-week. Today, Friday, fares are higher than at the beginning of the week.

So is there a trend in how airfares rise and fall in price over the course of a week? How does this match up with how airfares gradually rise as one gets closer to the date of departure? Is there a generally agreed sweet spot of when to book air travel?

Try this site: http://www.farecast.com/