If you haven't Googled a flight itinerary recently, you should try it.

Google's Flight Search, the fledgling search engine that lets you find a ticket and book it directly through an airline, is getting better. Much better.

In recent weeks, the new service has quietly expanded the number of U.S. cities it covers. (It won't say how many destinations are being served, except that the number has doubled.) Google has also integrated flight searches into its authoritative search results, making them easier to find and use.

When I wrote about Flight Search in the fall, it was widely regarded as a work in progress. But that work is progressing at a speedy clip. "Our goal here is to develop the best possible user experience," says Sean Carlson, a spokesman for Google.

But for whom is the upgraded Flight Search better? For customers like you and me? In the short term, yes. We get to find cheap flights through its slick and blazing-fast search engine, which is powered by recently acquired ITA Software.

For Google? Of course. A more functional site means more bookings, although the company declines to say how many tickets it has sold through this new flights interface.

For the rest of the travel industry, and particularly online travel agencies such as Expedia, Orbitz and Travelocity? Maybe not.

Those online agencies want to sell their tickets through Flight Search, and although Google says discussions about including the big three agencies are "ongoing," no agreement has been reached. Some think that the online agencies aren't a part of Google's business plan and will never be included. Buy a ticket through Flight Search, and you're taken to an airline website, although Google says that it's displaying search results from online agencies on a "test" basis under some results.

This little squabble is a sign of a much bigger challenge down the road — one that led Google's farsighted rivals to fight hard, but unsuccessfully, to block Google's ITA purchase.

Look around at other Google products. If you need to find something online, your first choice is Google's search engine. If you're looking for a sleek, intuitive email service, it's Gmail. A place for online video? Google's YouTube.

Google holds more than a 70 percent market share among online search engines. Gmail is one of the most popular e-mail services and certainly the easiest to use. Sites such as YouTube don't have any meaningful competition.

To suggest that Google isn't in travel to do anything less than dominate in the same way would be naive.

I can't imagine this breathtaking dominance escaping the attention of regulators much longer. But if it does — if Google takes over travel — there could be serious consequences that could harm consumers and businesses.

What if Google drives one or two online travel agencies, or a company such as Kayak, which searches multiple sites for flights, out of business? Where do we go when our only viable option is Google?

"Consumers would pay higher prices for airfares and other products and services as a result of Google coming to dominate the online travel market," predicts Ben Hammer, a spokesman for FairSearch, a coalition of travel companies that compete with Google.

Do we really want to live in that world?

Christopher Elliott is the ombudsman for National Geographic Traveler magazine. You can read more travel tips on his blog, elliott.org, or email him with questions at celliott@ngs.org.