Expedia (NASDAQ: EXPE) is ready to take flight after the Justice Department announced it wouldn't stand in the way of the online travel agency acquiring Orbitz Worldwide (NYSE: OWW), concluding "the acquisition is unlikely to harm competition and consumers."

Expedia declared in February its intention to take over its rival in a deal valued at $1.3 billion in cash, right after it had finished acquiring Travelocity and Australian travel site Wotif.

The purchase of Orbitz had some worried that it would essentially reduce the U.S. OTA market to just two competitors, Expedia and Priceline.com (NASDAQ: PCLN), and would concentrate three-fourths of the domestic market for third-party online booking into Expedia's hands. But the market is still much broader than that as consumers can still search for travel deals on Google, for example, or directly from the airlines and hotels themselves. There's always AirBnB and other sharing sites too.

That was the conclusion the Justice Department came to as well, noting that while "Many independent hotel operators, for example, do not contract with Orbitz, and those hotels that do often obtain very few bookings from its site," the industry itself is undergoing a major evolution, and pointed to TripAdivsor's new Instant Booking feature and Google's Finder app for flights and rooms that also let's you book through it.

Although they didn't think the OTAs would impose new fees as a result of the reduced competition, it's also possible sites like TripAdvisor could reap a windfall as hotels book more deals with them for fear of the pricing power Expedia and Priceline will wield. Other hotels might even push their own sites more aggressively, too.

In addition to Orbitz, Expedia also owns CarRentals.com, Hotels.com, Hotwire, Travelocity, and Trivago. For its part, Priceline owns Booking.com, Kayak, agoda.com, rentalcars.com, and OpenTable.

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Rich Duprey has no position in any stocks mentioned.

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