NEW YORK (CNN/Money) - United Airlines announced Wednesday it is raising its fuel-surcharge by $5 a flight, less than a week after a fuel-inspired $10 fare hike was dropped by most major carriers.

United, a unit of bankrupt UAL Corp. and the nation's No. 2 airline, said that the surcharge applies to fares in first and business class, unrestricted fares and some discounted economy fares.

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United and many other major carriers have had a $10 a flight surcharge in place since February 2003 on more expensive seats or on discounted seats on routes where they do not face competition from lower cost, low-fare carriers such as Southwest Airlines or JetBlue.

Last week Continental Airlines announced a fare increase of about $10 on most flights, citing the rising cost of jet fuel. United and many other carriers matched that increase.

But when Northwest Airlines did not go along with the increase, the airlines all dropped the fare increase Monday.

One air fare expert said he doubted the United surcharge increase would have a much better chance of taking hold.

"We've had surcharge increases tried since Dec. 17," said Tom Parsons, president of Bestfares.com. "The one Continental tried last week lasted longer than any of the others."