The U.S. Department of Justice is reviewing the Google-ITA Software deal.
A Google spokesman says the DOJ made a second request for documents and information early this week.
The Google spokesman expects the DOJ to approve the deal, which could close in "a couple of months."
Google had to execute a Hart-Scott-Rodino Act merger filing with the Federal Trade Commission and DOJ soon after the July 1 deal announcement, and after 30 days, the two agencies decided DOJ would handle a review and requested further documents from Google and ITA.
Opponents and proponents of the $750 million deal likely already have been communicating with the DOJ about any anticompetitive concerns and would continue to do during the review period.
The DOJ"s options include approving or modifying the deal or suing to block it.
In its public policy blog, Google updated readers about developments and cited statements by Kayak, Orbitz, Continental Airlines and Arthur Frommer, which Google interpreted to mean that the deal doesn't raise any anticompetitive concerns in the online travel marketplace.
Writing in the blog, Andrew Silverman, a senior product manager at Google, writes of the DOJ review: "While this means we won't be closing the deal right away, we're confident that the DOJ will conclude that online travel will remain competitive after this acquisition closes."