It happens all the time: You’ve just arrived at the airport and your flight gets massively delayed. For many fliers, that means having to kill hours of time by strolling through the terminal or scrolling through your phone. But if you’re savvy, and more than a little lucky, you instead might get yourself on the standby list for an earlier flight — and get to your destination before you’d even planned. Flying standby can be like a game of airport roulette, in which your time is money, and it comes with fewer of the risks. You’re hoping that a seat may become available on another flight. As long as you’re trying to get on an earlier flight and not a later one, though, you won’t lose your original seat if you prove unsuccessful.

Flights in general are fuller these days, which means fewer spots are available for standby passengers. And travel mishaps, weather delays and mass disruptions like this summer’s CrowdStrike IT outage can hamstring flights’ capacity further, said Gary Leff, founder of the blog View from the Wing.

“Your flight might get canceled, and your airline may not have seats for days,” Leff said. “At peak travel times, other airlines may not have seats available to help out, either.”

In the past, it would be normal to walk up to the gate of any flight headed for your destination and try to get on it. But changes to airline rules in recent years have restricted and complicated standby flying, said Julian Kheel, the founder and chief executive of Points Path, a company that helps people utilize their travel rewards.

Learn these rules and tips to navigate the standby hustle — and give yourself a better chance:

Know airlines’ policies

Standby policies are not the most straightforward, and they can differ from airline to airline. But there are some constants.

Almost always, you can fly standby only on the same day and with the same airline as your original flight, which means your airline has to have multiple flights to your destination. Flying standby also is a very American phenomenon; it’s generally only available when you’re ticketed on a domestic carrier, and the itinerary usually needs to stay within the United States.

“Many European airlines don’t allow it at all, at least unless you have a fully flexible ticket, which most customers don’t,” Leff said.

If your original itinerary has a connection, you may not be able to fly standby for a nonstop flight to your destination, Kheel said. And some carriers, like Delta Air Lines, don’t let customers fly standby if they originally purchased a basic econ-