Using a bunch of algorithms, some fancy computers, a little bit of complicated math, and what must be some sort of new magic, one man has successfully charted when air fares will go up and down, plus what the new prices will be.

According to a recent feature in Wired magazine, Oren Etzioni became perturbed after realizing everyone sitting near him on a domestic flight had gotten a better deal on their ticket.

Hellbent on rectifying those wrongs, Etzioni used his computer lab powers and the resources of the University of Washington to establish what is now called Farecast. It keeps track of 175 billion fares originating at 79 American airports.

In the article, Etzioni shares some interesting trade secrets. Here are a few of the most surprising:

#2.) Buying tickets super far in advance doesn’t always give you the cheapest rates. The research shows the lowest rates occur from eight to two weeks prior to departure. The exception to this rule is for Spring Break, Thanksgiving, and Christmas. Get those tickets as early as you can to get the cheapest rate.

#6.) The day of the week you buy a flight is almost as important as the day you fly. Everyone knows flights on the weekend are more expensive, but it also turns out most cheap fares are released early in the week. So check your fares on Monday night and Tuesday if you want the best deals.

#8.) Staying an extra day around the holidays can save you over $100 on your return flight.

Check out the rest over at Wired.

Oren Etzioni’s project :Farecast

Wired: Tracking Air Fares, June 23, 2008