Fliers, frustrated by high fares, full airplanes and a lack of amenities, gave the airline industry its lowest customer rating in seven years, in a national survey to be released today.

On a scale of 100 points, the airlines collectively received a rating of 62 in the University of Michigan's American Customer Satisfaction Index.

"If not for the improved performance of Southwest, the airline industry would have broken a record low," said Prof. Claes Fornell, who founded the consumer index.

While fliers may be looking for friendlier skies, a Monday report from Wall Street shows survival as the focus of many big airlines. J.P. Morgan analysts widened their 2007 operating loss estimates for the airline industry -- from $4.6 billion to $7.2 billion because of record fuel costs. Nor are they optimistic about a reversal of fortunes for 2009, when they project airlines will tally operating losses of $8.1 billion.

Although Northwest Airlines ended the first quarter with $3.4 billion in total liquidity (defined as cash and access to credit), the analysts projected that fuel prices could dramatically erode Northwest's cash reserves and result in a liquidity position of only $1.6 billion by the year's end.

Northwest and Delta Air Lines, proposed merger partners, exited bankruptcy last spring, but the J.P. Morgan analysts raised the specter of repeat Chapter 11 filings for some carriers.

The report listed United Airlines, Northwest and US Airways as the most vulnerable to future bankruptcies. Stock prices of all major airlines fell Monday, with the biggest slide occurring with United shares, which were down about 10 percent. Northwest stock closed at $8.09, down 4.5 percent.

Southwest, which led the pack of big airlines with a customer satisfaction score of 79, is the only major U.S. carrier that is not being hammered by high fuel prices, because the Texas-based carrier hedged much of its fuel supply at lower prices.

Northwest and Delta finished in the middle of the customer satisfaction field among network carriers, although Northwest's rating fell 6.6 percent.

Continental and American airlines each logged scores of 62, with Delta and Northwest trailing close behind with ratings of 60 and 57 respectively.

Delta's rating rose slightly, by 1.7 percent. Delta spokesman Anthony Black said his airline expects its marks to rise as Delta outfits more cabins with lie-flat seats in BusinessElite and leather seats in coach. In addition, he said Delta is offering more on-demand entertainment as well as better food choices.

United, with a score of 56, and US Airways, with a rating of 54, received the lowest marks from consumers in the first quarter of the year.

Three years after the US Airways-America West merger, the new US Airways is still struggling with integration issues. US Airways had the biggest drop in customer satisfaction at 11.5 percent.

Tammy Lee, Northwest's vice president of corporate communications, said Monday that thousands of employees recently completed training through a program called the Northwest Experience, which is designed to help flight attendants, customer service agents and other employees do a better job of meeting passenger expectations.

That training promotes better communication among Northwest employees and gives them the ability to solve problems as they crop up, Lee said.

In his report, Michigan's Fornell said that "mergers have often been bad news for customers" and that he was particularly skeptical of a potential United-US Airways pairing.

In the case of the Delta-Northwest merger, Lee said people from both airlines already have begun work on how to blend the two carriers as smoothly as possible. "We have teams dedicated to the customer experience and every other area," she said.

Liz Fedor • 612-673-7709