Until now, Google Flight Search only provided access to data about flights operating within the US region.
Google spoke about the new updates:
Since we launched Flight Search, we’ve heard from many globetrotters eager to use the feature to search for destinations outside the U.S. Starting today, you can find flights, including international destinations, from the U.S. quickly and conveniently.
At this stage we’ve included more than 500 airports outside the U.S. If your ideal destination isn’t yet available, we’re working hard on expanding our global coverage and adding more routes in the future. Our goal is to make booking travel as fast and enjoyable as possible.