Google has unveiled its flight search portal, Google Travel. The feature will initially be limited to some U.S. cities and show results for round-trip economy flights only.

A Flights link appears on the left side that leads to the new Flight Search feature, where users can make changes to dates, destinations, and filters much more quickly than it takes on most travel sites. The feature also displays a simple list of relevant flights, a way to see which travel dates are least expensive by dragging the date selector forward or backward and to compare lots of dates at once on a bar chart.

Users can also explore possible destinations, filtering by airline, flight time, and price. For example, users can view a map and use filters to see where flights will take them for a specific amount of money. It’s a fairly simple web interface, and Search Engine Land says that Google will also be experimenting with advertising. And the portal doesn’t feature one-way or multi-city fares.

For now, travel search just focuses on flights but it should be interesting to see if Google will add hotels, and more to the search site. The big question is how Google meaningfully entering the travel search market (armed with ITA Software) will impact its competitors like Kayak, Expedia and others. Kayak and Expedia currently offer more feature-rich search portals.

But Google is a giant in the search space, so it’s not unreasonable to think that the company could capture serious market share in travel search. Kayak issued this statement in response to Google’s travel portal. We’re confident in our ability to compete, and we believe our flight search technology is superior. We recognize Google is a formidable competitor but they haven’t been successful in every vertical they’ve entered. We use multiple data sources and proprietary technology, all of which helps us in our efforts to provide people with comprehensive, fast and accurate answers to their flight search needs.