UPDATE: Google has now talked a little more about the test. Blog post from Google here. It is understood Innovata is being used alongside OAG for the data.
The service is currently available in ten languages, Google says: English, French, Italian, German, Spanish, Dutch, Brazilian Portuguese, Polish, Russian, Turkish, and Catalan.
The post says:

"While this flight schedule feature does not currently use ITA’s search technology, this is just a small step towards making richer travel information easier to find, and we hope to make finding flights online feel so easy, it’ll feel like... well, a vacation!"
ORIGINAL:
An experiment by Google to show flight journey times and airlines operating a route is to be rolled out more widely in the next few days - but not all is what it seems.
The test was first seen in the UK earlier this week, basically adding information to a user's organic results when a search along the lines of "flights to barcelona" is entered.
When the user selects the "show all non-stop routes to Barcelona" tab, for example, they are shown a list flight times and available airlines serving destinations:
The functionality was difficult to examine further as only a limited number of users were able to view it. But now with the slow spread elsewhere around the world it is easier to see what is going on.
When a user clicks on one of the destination names their search is automatically changed to produce results including original search destination and the selected city.
However, it is not the organic search results which draw the eye, it is detailed listings contained a new box in the results, showing times of flights each day from the origin to the destination, what days the flight operates and the carrier.
In this case, Brussels to Barcelona:
Click on a popular route, say London to Barcelona:
When a user clicks on an airline link in the original results they are redirected to the homepage of the carrier, rather than a pre-populated search screen containing origin and destination airport.
Depending on the carrier, location of the IP is either not acted on at all (in the case of EasyJet) or automatically lands the user on the relevant country/language page (Iberia).
Google is using its stock answer when asked about the experiment, declining to discuss it any detail except for the standard "it's just a test."
But behind the scenes there is a lot more going on. Google has been quietly reassuring and seemingly very keen to stress to advertisers and partners that the latest flight information test is "nothing to do with ITA" or "ITA not running this."
The level of detail in the information provided in the search results can come from a few sources but, most likely, flight schedule supply giant OAG.
The formatting of the results is pure-OAG and, it turns out, Google has actually been a customer of OAG (licencing its data) for a number of years, although it has never admitted as much.
So, not the first fruits of the ITA acquisition, but perhaps an indication that Google will be pulling in content and data from other sources when it eventually takes the covers off its shiny travel search product.
NB: Thanks TOD for the images, screengrabbed from a computer in Germany.