After the acquisition of ITA, Google has now access to a lot more information about flights and even provide more information when you enter a flight releated query like [flights to Barcelona].
In this matter, Google begin started to test a more advanced OneBox for flight-related searches. Right now, when you search for [flights from London to Barcelona] Google links to services like Expedia, Orbitz or Kayak. The OneBox is useful, but it doesn't show a list of flights.
Here's the experimental flight OneBox, as spotted by SEO Gadget:
When you click "expand all non-stop routes to Barcelona", Google shows a very long list of cities. It's probably the biggest and most overwhelming Google OneBox. Maybe a drop-down would've been more useful.
After selecting one of the cities, Google sends you to a new search results page that shows a long list of flights.
It's nice to have all this information at your fingertips, but it's too overwhelming and these kinds of details aren't suited for an OneBox. Richard also noticed that "you get to data, with no call to action. I think this means most folks would be forced to repeat their search again on a flight provider."
[Via: SEO-Gadget, Thanks Alex]