Google is apparently testing travel. Here's Reuters' write-up. I'm on a break from a private equity conference and on a PAINFULLY slow connection, so I can't check it out right now.
Per Search Engine Watch, here's an example of a search re flights from Seattle to Boston. Here's JFK to Oakland (my flight tomorrow).
It's a kind of meta-travel/flight search that makes it relatively easy to check multiple aggregators and travel sites for the same flight. As a "travel vertical," it's obviously incomplete. But because of its relative ease-of-use — it's quicker to enter two city names rather than engage in the structured searches on the travel sites/aggregators — it would likely gain quick adoption.
Whom it most directly affects is not clear at this point. Does it dilute or reinforce the Orbitz brand, for example? Too early to tell. The lesser-known travel meta-search sites such as Sidestep and Kayak are likely the most vulnerable, however.