If you have access to the web, chances are you’ve heard of Wordle by now. The online word game, which gives players six chances to decipher an unknown five-letter word, has become the internet’s latest obsession—so much so that it’s already inspired countless spinoffs.

One such spinoff was designed with travelers in mind: Airportle. Created by Scott’s Cheap Flights, an online service that helps travelers find the best deals on airfare, Airportle works just like Wordle, but instead of guessing words, players are tasked with deciphering airport codes. After submitting their first guess, players will see the letters they’ve chosen highlighted one of three colors: green if the letter is correct and in the correct spot, yellow if the letter appears in the airport code but in a different position, and gray if the letter does not appear in the code.

You might think that reducing a five-letter challenge to a three-letter one would make this version of Wordle easier. But considering Airportle draws from the International Air Transport Association (IATA) list of airport codes from all over the world, it poses a serious challenge for even the most seasoned travelers—and makes for a particularly great way to pass the time next time you find yourself twiddling your thumbs at, say, LAX, JFK, or ATL.

Like Wordle, Airportle only issues one challenge per day, meaning there’s no risk of getting caught up in a hot streak and missing your flight. But if you do have time for a few extra rounds, check out some of the other spinoffs, too, like Taylordle for Taylor Swift Fans, BRDL for bird lovers, and Sweardle for potty mouths. Pro tip: You can also play Wordle in other languages, so maybe consider brushing up on the mother tongue of wherever it is you’re traveling.