If you guessed Kayak then you’d be right. They are utilizing the lessons learned on their iOS and Android applications to build a better web experience, see article. They are just the latest company to move to a “mobile first” approach. The idea is simple as it uses a focused user experience to deliver across multiple screens. Even if the primary consumption of the site is done on the desktop “mobile first” is a simplification of core services that offer users a better experience across different screens. ESPN is another company that is taking this approach with some of their recent design decisions. You can see the mobile view directly on your desktop and compare that to the full site view.