Google Now has been showing off alternate info for when your flight's been delayed for a bit, and as of late the app's looking to take another bite out of air transit frustrations: keeping an eye on ticket prices. Poking around on Google Flights for a trip will drop a card into the search giant's digital assistant now and will alert you when prices change based on your recent destination or itinerary searches. It's sort of like what Airfare Watchdog does, but is possibly more convenient. As pointed out by by Android Police, however, it doesn't look like searching for a flight on the likes of Kayak or Travelocity will trigger the same activity.
Update: Google has confirmed the feature in a post on Google+ and explained how it works. It's only in the US for now, you will need the latest version of the Google Search app on Android, and yes, it has to be a flight you've searched for on Google. If all of that lines up and the price drops, boom, you'll have a notification coming through.