The best way to get a good deal on a flight out of the U.S. is to wait for another airline carrier to announce a new route, the Wall Street Journal wrote in a December 4 report. The news outlet looked at various airlines and how a competitor adding the same route affected price. In some cases, prices dropped nearly 50 percent for smaller airlines.

For instance, a flight from Austin, Texas, to Paris cost $831 with a connection on American Airlines. When Norwegian started a nonstop service in October, the price cost $569 for nonstop on Norwegian two weeks after they started the new route.

The Journal noted it doesn’t always work. But the best way to find out is to plan about six to nine months in advance and check if there are any announcements about new flights. “The easiest way to stimulate demand is with price,” Rick Seaney, chief executive of travel-data firm 3Victors, told the Journal.