Previously, the tool was for flights within the U.S. Now international destinations are an option, according to a blog post today from product manager Eric Zimmerman.
"At this stage we've included more than 500 airports outside the U.S.," Zimmerman said. "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."
There's a big caveat here, though. The service only includes international destinations if you're starting from the United States. So it remains fundamentally a U.S-based service.
The service is the result of Google's $700 million acquisition of ITA Software. The tool lets people search for flights and use graphical tools to pick the most economical options by adjusting dates, for example. See the screenshot below.