Five days ago, Google and ITA Software announced that they'd reached a "definitive agreement" covering an acquisition. Only - if you hadn't already guessed - it looks like a government agency may have a thing or two to say, as a new report indicates that antitrust regulators will take a close look at the transaction. The main concern is that Google might eventually withhold flight data (which ITA provides) from its search rivals (Bing is one ITA customer). The search giant's only promised to honor existing agreements so far.