MARK AUSTIN THOMAS: What do you do if you're an airline and the airport raises the rent? You slap a surcharge onto your tickets. That's what United Airlines is doing for flights leaving from one major airport, Los Angeles International. Ten bucks a ticket will be added on to the bill starting immediately. Marketplace's Lisa Napoli says get ready for more.

LISA NAPOLI: LAX blames the rent hike on all the upgrades it's got to make at the airport. United says as a result, it'll pay $10 million more in rent each year, and that it's got to pass along costs.

BOB MANN: Well, I think it's United testing the market.

That's airline industry expert Bob Mann. He says United didn't raise ticket prices because that would make the airline less competitive in online ticket searches. And he expects other airlines might slap on a surcharge too.

MANN: But in fact, rising airport fees are an area of considerable concern to the airline industry as a whole.

Meanwhile, airlines have banded together to fight the airport authority. They're suing for what they say is a violation of their lease agreement.

In Los Angeles, I'm Lisa Napoli for Marketplace.