Google Flights introduces airfare price guarantee program.

Google Flights is testing a new price guarantee program that will monitor fares even after customers book their flights. If it finds a lower price, customers can receive a refund for the difference. Only flights departing from the U.S. are eligible for the program, and customers must book directly on Google Flights to be eligible for a refund. The program is still in its early testing stages, and it's not easy to find a route on Google Flights with a price guarantee.