Google announced on Twitter they are previewing a new design and feature set for the Google Flights search. You can access Google Flight Search at google.com/flights and from there, you should be able to request access to the new design.
It says “The new Google Flights has landed! Try the updated design with new tools to help you find and book flights with confidence.”
Here is a screen shot of the old interface:
Here is the new user interface:
— Google Travel (@GoogleTravel) November 20, 2017
Forum discussion at Twitter.