A dispute over rents between Los Angeles International Airport and its airline tenants has grown beyond an internal fracas and is now affecting passengers departing the airport.

United Airlines has announced – and American, US Airways, Northwest and Delta have matched – A $10 per passenger surcharge for their passengers departing from LAX.

United says the $10 fee added to its regular fares will offset the higher rents the airport is imposing.

The airport says it needs the money to pay for improvements. United’s additional costs amount to about $10 million a year, the airport contends, but it will collect about $48 million with the $10 per passenger fee.

Still standing on the sidelines is SeaTac-based Alaska Airlines, whose own terminal costs will increase by several million dollars yearly, is still mulling over it’s reaction, said Alaska spokeswoman Amanda Tobin-Bielawski.

Alaska has the largest share of business between Seattle and LAX. United is its main rival on that route. Not joining the surcharge parade would put Alaska’s fares nominally below United’s on that route and would put its flights first on computer screens that sorted available flights by fare costs.

But Alaska could end up losing money if it declined to impose a surcharge and didn’t see its share of the business increase.