(NewsNation) — There’s a growing trend of people booking so-called “hidden city” tickets to avoid flight delays and save money.

The practice within the travel industry is called “hidden city” fares, or “skiplagging.”

It works like this:

When trying to book a flight to a desired destination, travelers look to buy the cheapest airfare — even if that means booking a flight to a city that isn’t their final destination.

Say someone is trying to book a flight from Chicago to Charlotte on Friday night. Rather than pay $191 for a one-way direct flight to the Queen City, a ‘hidden city” ticket costs just $117.

How? The traveler still ends up in Charlotte, the difference is they’ve booked a flight from Chicago to New York instead with a connecting flight in Charlotte. Once arrived in Charlotte, the traveler just doesn’t board the connecting flight to New York.

However, while it could save you money on airfare, there are a couple of downsides to “skiplagging.”

For one, travelers can’t check a bag. If they check a bag, it will end up in that final destination (New York) rather than the one they are actually going to (Charlotte).

Also, they won’t receive frequent flyer miles for the second, empty leg of the flight.

Airlines hate this practice. United Airlines even sued the creator of a hidden city travel website in 2015, claiming “skiplagging” was “deceptive behavior.” The judge dismissed the case, though, claiming the court didn’t have jurisdiction over the case, according to CNN Business.