We are big fans of concept designs of existing user interfaces. It gives us a chance to expand on what has been thoroughly examined before, through a fresh set of eyes. There are plenty of new redesigns for Facebook, Twitter, Netflix etc, which are all great. Some of those projects are worthy enough to be developed and launched for real.
John Noussis is an Athens based creative thinker and UX designer. He believes in delivering solutions that are based around users so as to effectively hone in on the best possible user experience possible. I found his entry on Google Flights via his Behance. It is an interesting dive into Material Design and how it has helped in achieve his interactions and manner of navigation throughout the design.
There is a subtle application of color throughout that make each screen and event refreshing while retaining a high level of consistency, no doubt through Material Design itself.
For more information on John Noussis, you can find him on his blog on Medium.