Continental did not raise fares.

The airfare increases come after a turbulent year in which big airlines have been beleaguered by higher fuel costs, underfunded pension obligations and fierce competition from discount carriers.

"With oil continuing to trade at historically high levels, all industries must act responsibly to offset rising costs," said United marketing chief John Tague.

Although crude-oil prices fell 81 cents to $58.09 a barrel yesterday, the futures contract flirted with $60 a barrel Monday, closing at a record $59.37.

Before yesterday, domestic fares had risen seven times since February, especially on routes where major airlines face little competition from discount carriers. Meanwhile, fares to Europe are the highest that passengers have seen in years.

Demand on both sides of the Atlantic is up — especially from Europeans, whose currency, the euro, goes a long way in the U.S. But the number of seats offered between the U.S. and major European gateways is up only 2 percent year over year, according to USA Today research. As a result, coach fares this summer are high, even booked a month ahead.

Travelers leaving on Saturday from any gateway city in the Eastern region of the U.S. will pay $1,000 to $2,000 round- trip for coach flights to Paris, Rome, Amsterdam or Frankfurt, Germany.

Travelers to London will pay more than $1,000 roundtrip unless they fly from New York.

"The Atlantic is very strong this summer, and it's surprising people," said Graham Atkinson, United's senior vice president of worldwide sales. "It's difficult to get a seat in economy in peak weeks and on weekends."

Passenger demand in Europe is growing 5 percent faster than in the U.S., Atkinson said. But the euro weakened to $1.21 yesterday after hitting $1.35 in January. That may explain why some U.S. travelers have decided to vacation in Europe after all. "We have two groups fighting for seats," said Tom Parsons, CEO of Bestfares.com.

Trips within the U.S. are also costlier. A July flight on Delta from Dallas to Albany, N.Y., would have been $323 round- trip if booked last fall. Today, it would be $456 roundtrip if booked 14 days ahead.

Even discount carriers are raising fares. Southwest flights from Cleveland to Los Angeles had been as cheap as $99 one-way. Now the best fare is $139, Parsons said.

Bargain fares to Europe in June, July and August are close to nonexistent. London is the cheapest gateway because it has more flights than other capitals and two major airports. From there, travelers can take a train or a European low-fare carrier elsewhere. Flying Tuesdays and Wednesdays is cheaper than weekends.