Google on Thursday announced that it is moving into the travel industry, buying a flight-information company called ITA Software for $700 million. But what does the entry of the Internet giant mean for companies already in the market, like Expedia, Priceline and even Microsofts Bing Travel?

ITA currently provides airfare data to many of the industry players, including Orbitz, Kayak and Bing; Google said on Thursday that it would honor existing agreements with ITA's customers. But despite such promises, Google is likely to...