Carolyn Kaster, Associated Press
A worker pulls a fuel hose up to a plane in Middletown, Pa., in late 2007. Fuel prices are spiraling U.S. airlines toward bankruptcy.

DALLAS — Higher fares and new fees are irritating air travelers, but airlines still can't raise money or cut flights fast enough to cover ever-higher fuel prices.

In the view of airline executives and analysts, the industry is facing its toughest challenge yet, with little prospect that carriers can return to profits anytime soon.

Even though most of the big airline companies have large cash stockpiles, analysts suggest they could burn through their cash and go bankrupt by early next year. Already, several smaller airlines have filed for bankruptcy protection or simply shut down in recent months.

"This is worse than 9/11," said Ray Neidl, an analyst with Calyon Securities. After the 2001 terror attacks, "at least you knew passengers were coming back. Oil at $130 is unsolvable."

Among the largest airlines, analysts rate US Airways as the most likely to be pushed into bankruptcy, followed by United Airlines parent UAL Corp.

Bill Warlick, an analyst with Fitch Ratings, said US Airways Group Inc. could face a crunch next winter if revenue drops in the slow fall travel season and fuel remains at current prices. He said the airline has fewer options for raising cash — it can't fetch as much by spinning off assets as others — and without strong international routes is more vulnerable to a weakening U.S. economy.

Just a few weeks ago, mergers were the talk of the airline industry. Delta Air Lines Inc. announced it would buy Northwest Airlines Corp., and executives of other carriers met to discuss other deals that analysts said would lead to bigger but more efficient airlines that could survive in a world of high-priced oil.

But the price of oil has nearly doubled in the past year and jumped 13 percent in just the last month, scrapping all those merger calculations and making airlines worry more about hoarding cash.

"This is going to hurt the consolidation effort," said Roger King, an airline analyst for CreditSights. "When you put two companies together, there are up-front costs, and cash is tight everywhere. American has more than $4 billion in cash, but that can go pretty quickly."

So airlines are raising fares — nearly a dozen times already this year — and mining other fees, anything to bring in money.

Airlines were already charging $25 to check a second piece of luggage, but American will break new ground next month by charging $15 for the first bag.

American also announced Wednesday it would cut 11 percent to 12 percent of its U.S. flights later this year and lay off workers — probably thousands of them, although officials declined to give a figure. United announced last month it would cut 1,100 jobs and reduce flights, and Delta wants to cut 2,000 jobs.

Both United and Delta have already announced plans to cut capacity about as much as American, which would reduce their fuel burn and leave travelers fighting for seats on fewer planes.

Herb Kelleher, the iconic co-founder of Southwest Airlines who stepped down as chairman Wednesday, said flying could become something that only business travelers or the affluent can afford, much as it was in the 1950s and '60s.

"You may see a lot less air service across the United States, and that's really a shame," Kelleher said. "We are heading back in that direction."