We've been praising the virtues of ITA Software's Matrix a bit lately, and for good reason. The travel search engine has a clean interface, digs deep to turn up hard-to-find fares, and most of all is free to anyone to use.
Here are some other reasons we like it:
It shows elusive K-Up fares. Want to automatically upgrade to business class from coach, but hate the thought of paying full-price? Just type in one of ITA's advanced routing codes to find those coveted and oh-so-elusive K-Up or Y-Up fares. HackMyTrip says the best code to use is /f bc=w|bc=y. Plug it in after the airport code to see what comes up.
Fares shown are "all-in." This means you don't have to worry about hidden taxes getting tacked on later. Too bad the airlines don't do this already, especially with baggage and other pricy add-ons.
Matrix calculates the price per mile of every fare. This is great for determining whether a trip is worth its salt. The Flight Deal sets its criteria for deals at 6 cents per mile, a price point they say hits the "sweet spot" for cheap-o fares, and helps them to rack up miles to put toward rebates.
No-frills customization. Flying from La Guardia to San Francisco on American Airlines, but hate the thought of a layover in Houston when you could kick back in Denver? No worries, just input some codes and Matrix will dig around to come up with the ideal fare. You can even use the Time Bars view for a colorful look at how long you'll be twiddling your thumbs. For more seasoned travelers, knowing advanced routing codes can be useful for "mile running" (racking up miles) or finding cheap fares.
The downside. Of course, not every travel site is created equally and the Matrix isn't perfect. The biggest downside is that you can't book fares directly on the site and using the advanced routing codes does take some getting used to.
Sometimes you'll find a great fare going one-way, and a lousy fare on your return flight. The only way to score the price point you're after is to settle for both. That said, Matrix is still quite useful for finding the type of fare you want, and arming yourself with specific information when you call the airline to book.
SEE ALSO: 23 secrets to booking cheap flights >
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