Expedia's agreement on Thursday to buy Orbitz for $1.33 billion marked the latest in a spree of acquisitions it and the larger Priceline Group Inc (PCLN.O) have made to become the world's dominant online travel agencies. Experts say the companies' followings give them power when negotiating contracts with hotels and airlines, which to varying degrees rely on the sites to sell their products. Combined with Orbitz and Travelocity, which it acquired in January, Expedia received about 39 million unique website visitors in December 2014, according to Internet analytics company comScore Inc. These mergers "strengthen Expedia's position in the distribution chain and could have implications for consumers, travel agents and airlines," Melanie Hinton, spokeswoman for the trade group Airlines for America, said on Friday in an email. "We would expect the Department of Transportation and the Department of Justice to carefully examine these transactions and their impact on consumers and competition." Get the full story at Reuters