Q: What’s your personal favorite site for searching airfares? I’m partial to Kayak.com, but sometimes I use Travelocity and Orbitz. Is there one site that’s best for last minute deals? What about Mobissimo?

A: There really isn’t one “magic bullet” Web site, even though travel techies have been trying to build one for years.

One of the problems is that low fare leader Southwest Airlines, now the largest US carrier based on domestic passengers boarded, doesn’t release its fares to any site other than its own. That’s also true of new low fare airline SkyBus, and Allegiant. Plus, those Spirit Airlines 1 cent or $1 fares, which you can sometimes actually book, only appear on Spirit’s site.

When I’m booking my own travel, I’m usually flexible in my dates, so I start my search with Travelocity, using their flexible search option, for domestic flights (I know, it can be slow and clunky, but I am too sometimes). Cheapair has a good flexible search, too, but only for domestic and US-Canada round-trips, and it's an especially clean and easy to use site. I also like Orbitz’s flexible search, which also includes flights from the US to foreign lands. If I’m looking for a flight between two foreign countries, I use Travelocity’s Canadian affiliate at www.travelocity.ca, or Mobissimo.com.  Caveat: You can’t book travel, if you’re a US citizen, on Travelocity Canada, where the fares are listed in Canadian dollars (but the US dollar is almost on par with the Canadian, so you can just deduct 10% to get an idea what it’ll cost in greenbacks). However, these sites don’t include all the discount foreign airlines, such as Ryanair.

The advantage to Kayak is that it doesn’t charge a booking fee. The same is true for Sidestep. However, neither site includes Southwest, SkyBus, Allegiant, and some other super low cost airlines. And they don’t include many of the international airlines’ lowest discount fares, which can only be bought on their own sites.

And Kayak, Sidestep, and Mobissimo don’t have a good flexible date search, so if you’re willing to adjust your travel dates to find the best deal, these sites are not for you. The same can be said for individual airline sites: very few have a good flexible search function (American has a 31-day flexible search, but only for domestic round trip fares).

Many people search on third party sites such as Travelocity and then book the fare on the site of the airline offering the lowest fare. This does help avoid booking fees, and gets you bonus frequent flyer miles. The only downside with this approach is that if everyone did this, the third party sites would go out of business. You’d be killing the golden geese. And sometimes, it’s just plain easier using a Travelocity or Orbitz than it is to use an airline site.

As for last minute deals (when you have less than a 7-day advance purchase), I suggest lastminute.com (formerly Site59), priceline.com, and Hotwire. People either love or hate these sites, but if you're desperate for a last minute deal they can be your best friends.