United Airlines and travel-booking service Orbitz are suing Skiplagged, a small startup that helps travelers breach the airlines' pricing schemes to acquire better deals by finding "hidden city" fares, reports TechCrunch.

In November, United Airline and Orbitz filed a civil lawsuit against 22-year-old Aktarer Zaman, who founded Skiplagged.com last year. The two companies allege that Zaman used the website to "intentionally and maliciously interfere with [their] contracts and business relations in the airline industry [...]" and "by promoting prohibited forms of travel on Skiplagged, Zaman has induced breach of Orbitz Worldwide's travel agency contracts with commercial airlines and of United's customer contractual relationships."

Airline pricing is complex and confusing. It is often less expensive to buy a ticket from Philadelphia to Orlando with a stopover in Chicago even though you just want to go to Chicago. You simply remain in Chicago instead of taking the next flight segment to Orlando. As strange as it may sound, sometimes it is cheaper to buy a ticket for a multi-leg flight rather than a regular one-way ticket.

By the way, it only works when you do not check luggage.

The airline industry calls this a "hidden ticket" fare. Most airlines ban the practice.

It is against airline rules to book flights with the intent to not fly to the ticket's final destination, but savvy fliers have used this strategy to obtain better fares. United Airlines specifically prohibits this practice in its Contract of Carriage, and the consequences include charging you the regular fare, deleting your frequent flier miles and taking legal action.

According to Zaman's post on Reddit, Skiplagged.com was launched last year as an airfare search engine capable of finding hidden-city opportunities and ways to combine two one-ways for cheaper than round-trip costs. Zaman claims to save consumers up to 80 percent when compared with the cheapest findings on other sites, like KAYAK.

"[Hidden city ticketing] have been around for a while, it just hasn't been very accessible to consumers," Zaman told CNNMoney.

Zaman also told CNNMoney that he expected a lawsuit but that there's nothing illegal about his airfare search engine.

He claims to have made no profit from the website that exists solely to help travelers get the best airfares by exposing an "inefficiency" in airline prices that frequent fliers and travel agents have known about for decades, according to CNNMoney.