A New York computer whiz is facing a lawsuit from United Airlines and Orbitz over his site, Skiplagged.com because his site promoted “hidden city” travel.

The site, created by 22-year-old Aktarer Zaman, helped consumers find “hidden city” flights, where you buy a ticket to one destination, but you really only plan on going to the city where you have a layover. These flights aren’t always cheaper than direct ones, but they usually are.

For example, a “hidden city” flight would be like buying a ticket from New York to Los Angeles, when you really want to go to a smaller destination, where your layover is. It only works if you don’t have any checked baggage, since the bags would go to LA.

CNN Money reports that United and Orbitz called Skiplagged “unfair competition,” especially since it promotes a “strictly prohibited” travel strategy. They are asking for $75,000 in damages.

Zaman told CNN Money that he didn’t invent “hidden city” booking and he hasn’t seen any profit from helping travelers get the most value in air travel.

“Use of hidden-city ticketing can save a lot of money, and airlines aren’t in the business of promoting, allowing or turning a blind eye to practices that can break the system down,” Randy Petersen, publisher of InsideFlyer magazine, told Bloomberg about the practice.

Peters on added that small corporate travel departments will occasionally use the practice as well to help out customers.

A United spokesman told CNN Money, “This practice violates our fare rules and we are taking action to stop it to help protect the vast majority of customers who buy legitimate tickets.”

Zaman began a GoFundMe page to help pay for his legal fees. So far, he’s raised $14,900 of his $20,000 goal.