When the price of an airline ticket can change several times a day, it's hard to feel secure about locking in the lowest fare. But several Web sites are adding features intended to help you feel confident about the price you're paying.
FareCompare.com offers historical prices for trips in 77,000 markets in the U.S. and Canada -- data that haven't been available before to consumers. Farecast.com goes a step further, using sophisticated data-mining techniques to predict whether prices for a particular trip are likely to go up or down over the next week. Kayak.com now has a feature called Buzz that shows the best prices found by other Kayak users on the most searched destinations over the past 48 hours.
Airlines monkey around with ticket prices as much as three times a day for domestic itineraries and prices can change on international trips as often as five times a day. What's more, fares on a particular flight can change quickly -- up or down -- as seats sell or remain empty. A lack of sales can prompt airline computers to offer more seats at a lower price.
http://www.FareCompare.com http://www.FareCast.com (currently for Seattle and Boston only)
(From the Wall Street Journal)