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 economy ticket.

Another key component is your luggage. Some carriers, like American Airlines, won’t let passengers stand by for a flight if they have checked a bag, unless they have elite status.

“Even for airlines that do allow it, it complicates the process and can mean your checked bag arrives on a different flight than you do,” Kheel said.

How airlines rank standby fliers

With limited seats available on other flights, beating fellow standby hopefuls is part of the game. Kheel said travelers who get that will check for other departures ahead of time and monitor their flight’s status closely. Besides subscribing to notifications from the airline directly, consider downloading a third-party app like Flighty or FlightAware, which can provide up-to-the-minute flight alerts.

It’s not a full-on meritocracy from there, though. By and large, frequent fliers get first dibs when airlines prioritize their standby lists. “Having status with an airline helps, since it puts you to the top of standby lists most of the time, meaning you’ll clear ahead of other passengers trying to do the same thing that you are,” Leff said.

There can be other factors, too, such as what class of service you’re flying in, how expensive your ticket was and whether you hold the airline’s credit card.

Standby rules for paying passengers differ from the rules for airline employees and their companions (called nonrevenue passengers). A bit confusingly, both groups are listed on the same standby list you see on airport monitors and airline apps.

One exception that can upend a standby list’s rules: A nonstatus passenger whose travel was canceled or disrupted typically will get priority over a status-holding passenger who’s just choosing to get on that flight. So, if you’re on a standby list and wonder why so many passengers suddenly jumped ahead of you in the queue, the reason might be a previous flight’s delay or cancellation.

Consider alternatives

When a traveler flies standby, it typically means something made them want to change their flight in the first place. If that’s your situation, there are some other options to consider. Kheel advised checking whether your reservation has same-day confirmed availability, which operates similarly to standby but comes with a guaranteed seat.

“The downside is that unless you have elite status with the airline, you’ll likely pay a fee for a same-day confirmed change, while flying standby is typically free,” Kheel said. United Airlines, for instance, charges up to $75 for confirmed same-day changes if you don’t have Premier status.

It’s important to think ahead because how you book a flight can make all the difference. When flight delays and cancellations occur because of mechanical issues or bad weather, a credit card that includes embedded travel insurance coverage can potentially save the day. In these cases, you’d be able to book a new flight under the terms of the policy — and you won’t have to deal with the airline’s policies directly. To qualify for coverage, a traveler must use that specific card to make their travel purchases and provide proof of a disruption, as with any type of insurance.

For a more advanced hack, consider booking a backup flight using airline miles. Just ensure, if you do, that the backup reservation isn’t on the same airline as your primary flight.

“Most airlines have computer algorithms in place that can spot and automatically cancel duplicate reservations made for the same passenger on the same day,” Kheel said. Also, make sure you’re booking a backup ticket that can be canceled, so those miles can be redeposited free.