So, where should you start searching? McGee advises consumers to shop the big three first to find the best rate. Then, he says, you should visit the site of the airline that's offering the desired fare and buy the ticket there. That way, he says, you can avoid the surcharges and $5 to $7 booking fee that a third-party site tacks on.

Where to search?

• If you're looking for a weekend getaway: Lastminute.com • If you're a spontaneous traveler with no time constraints: Priceline • If you're partial to the airline's site directly: travel search engines.

For travelers looking for a weekend getaway, Lastminute.com will serve you well. "It's great for people who don't have a specific place in mind when they go to a travel site, but know they want to get away," says Elissa Richard, associate editor of Shermans Travel and airlines editor at the magazine of the same name, a company that compiles offers from airlines, vacation package providers, cruise lines, hotels and more. "The site is designed to give these travelers a little inspiration."

If you're a spontaneous traveler with no time constraints, you may appreciate bidding sites such as Priceline. You can't always choose your airline or flight times, but, "They are good alternatives for people who don't have a lot of limitations," McGee says.

If you're partial to visiting the airline's site directly, travel search engines may be your best bet. "They scrape all the data from all the airlines and without adding any fees, they connect you to the airline directly," Richard says. She recommends Kayak for domestic travel and Mobissimo for international travel. Cfares is another site getting a lot of attention for its international deals.

What's great about the travel search engines is that they partner with hundreds of carriers, unlike the big three, which tend to partner with only major airlines. Kayak, for example, recently started showing fares from JetBlue. Plus, it has many user-friendly features -- it recognizes the cities you type in most often, thus saving you time.

Richard says Mobissimo is similar to Kayak, but tends to have better access to international fares due to its strong database of European airlines.

There's also a cluster of really innovative sites popping up. Newcomer FlySpy, which is still in its testing phase and only offers fares to and from a few cities, graphically shows you how fares to your desired destination trend over a 30-day period. This allows you to see which days of the week may be cheaper to fly -- and not just from the airport you selected, but from others nearby. "This is a great example of how travel sites are evolving," says Richard. "It's all about taking it to the next level of relevance."

Alana Klein is a freelance writer based in New York City.