By Charles Leocha

Travel columnist

updated 11:03 a.m. ET June 6, 2008

Charles Leocha Travel columnist • Profile • E-mail

When the Internet Age began with online airline bookings, there were basically four big guys on the block — Expedia, Travelocity, Orbitz and OneTravel.com. Yahoo had some sort of travel engine as well, but it didn’t get much attention. Today, the sector has exploded and the flight deals available on these sites can be very different.

I just went through a dizzying process of booking a flight from Boston to Venice for August. I was amazed at the differences in airfares. Here is a list of the Web sites I checked:

Kayak.com — Sidestep.com — Expedia.com — Orbitz.com — Travelocity.com — cheapflights.com — Airfare.com — Cheapair.com — Cheaptickets.com — Mobissimo.com — BA.com — Priceline.com — Vayama.com — AA.com — alitalia.com — Delta.com — 1800flyeurope.com — USAirways.com — AirFrance.com — Iberia.com — Cheapoair.com — edreams.com — and I’m sure there were more.

Whew!

All of these sites rarely had matching fares. Booking fees, airfares, connections, even airlines were different — it was chaotic. In the end, a combination fare presented by Cheaptickets.com was the winner, flying me from Boston to Paris on American Airlines and from Paris to Venice on Alitalia (on a flight operated by Air France).

The cost was $887 round trip. At the time I booked the ticket, it was more than $150 less than the next closest airfare.

This American Airlines/Alitalia ticket was a ticket between airlines that are not members of the same airline alliance or that share loyalty programs. The ticket could not be booked through aa.com nor through alitalia.com. It was a creation made possible by Cheaptickets combining fares that normally would not have been combined.

The lesson in my marathon search is that, today, it pays to try a collection of sites prior to purchasing rather than only three that I once recommended. In another search the airfare differences were in the range of $200 for identical routings. That can make a huge difference when they are multiplied by three or more passengers when families are traveling.

Don’t believe those “lowest fare” guarantees. There are so many variables that fulfilling the guarantee parameters is next to impossible.

Every site seems to have different deal with various airlines. For another flight, Airfare.com had the best rates out of Washington, but only until the end of August when evidently their deal with Iberia ended. With another online travel agency, American Airlines had better bargains than found on the airline’s own site.

Daily travel blog Daily postings from ‘the last honest travel site’

And keep checking code-share flights. Swiss Air Lines was selling seats on United flights from Dulles to Zurich for less that United, even though the flight was operated by United. My Alitalia ticket on Air France cost less than I could have purchased it from Air France.

Go figure.

Be careful of outrageous connections when booking cheap flights. The best deals often involve changing airports (especially those passing through London) or a full day sitting around the airport. Both are a real drag, especially when faced with these delays after a long, uncomfortable transatlantic flight. In my case, avoiding JFK is a priority.

Better yet, look for a travel agent that can do the legwork for you and who has access to additional consolidator fares.

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