One man’s attempt to cheat the system with air travel ended with a lawsuit against him.

The passenger booked a flight on Lufthansa Airlines from Oslo, Norway to Seattle. The flight had a layover at the airport in Frankfurt, Germany. The passenger got off the flight in Frankfurt and then didn’t finish the last leg of his journey.

Lufthansa then took legal action against him.

The practice is known as “hidden city ticketing.” Passengers attempt to get a cheaper ticket by booking a flight between two destinations, with a layover in the location they truly wish to travel to.

“When you purchase an airline ticket, you are essentially signing a contract,” says aviation attorney Erin Applebaum. "While this is not necessarily illegal, it is against the terms of the contract of carriage that you agree to when you buy your airline ticket.”

Applebaum says that by not complying with the terms of the carrier, you may open yourself up to legal action.

A European court dismissed the Lufthansa lawsuit, but the airline told CNN that it is planning to appeal the ruling.