Southwest boosts fares by $10 per round trip

— -- Southwest Airlines on Wednesday raised airfares on most domestic flights by $10 round trip.

If matched by other airlines, it would be the second airfare increase of the year. Last month, airlines raised fares by $10 each way on long flights.

Typically, when Southwest raises fares, others follow suit. American Airlines matched the increase late Wednesday afternoon.

One other attempt to raise fares this year failed when Southwest, the largest low-cost carrier in the nation, and other airlines refused to go along with it.

JetBlue Airways on Sunday also raised fares by $10 round trip to most of its destinations.

Ashley Dillon, a Southwest spokeswoman, says Southwest first rolled out the $10 round-trip increase in fares earlier this week in Florida, Las Vegas and Phoenix.

Wednesday, the airline spread the increase across its system except for flights under 500 miles and the highly competitive Denver market.

"We have increased fares to cover operating costs, including the high price of jet fuel," she says.

"Southwest is known as the low-fare carrier, and we don't nickel-and-dime our customers by charging fees for things like checked bags and changes."

Airlines are under pressure to make up for higher fuel costs. Other developments also are forcing them to re-examine their prices.

A new federal law requires them to disclose government taxes and fees when advertising prices.

That affects airlines such as Southwest and Spirit, in particular, because they often advertise low one-way fares.

The airlines face a proposal from the Obama administration to raise taxes on tickets to fund the air traffic system and security.

Overseas, a new European law requires airlines that fly into and out of Europe to pay for carbon emissions.

Last year, airlines tried raising fares 22 times. Only nine of the increases stuck. That was after two years of relatively stable airfares.

But Rick Seaney, co-founder of FareCompare.com, says airlines could have a more difficult time raising fares than last year.

"It is already difficult for U.S. airlines to pass on ticket increases to passengers who are still stinging from economic woes," he says.

"They will continue to try to raise prices. (But) by doing so, they are testing the appetites of both consumers and their peers. If either of these groups don't like the fare … they will be forced to roll back."