Southwest Airlines, the nation's largest domestic carrier, raised round-trip airfares $10 on about 400 of its routes--or 10% of the airline's flights.
So far, only United Airlines has matched the hike but has extended it to a broader range of routes, according to farecompare.com, a website that keeps track of airline ticket prices.
Since the begining of the year, five fare hikes have been initiated and matched by all the nation's biggest carriers. Several others have been rescinded when price increases have not been matched by the majority of the country's carriers.
Just last month, Southwest initiated the last hike, a $10 increase for round-trips of less than 500 miles. It was matched by all the major carriers.
Still, the number of hikes this year is low compared to 2011 when the nation's carriers approved 12 fare increases, saying the higher prices were needed to offset the higher price of fuel.
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Follow Hugo Martin on Twitter at @hugomartin
