NEW YORK (CNN/Money) - American Airlines has the final labor concession approval it needed to stay out of bankruptcy, but the world's largest air carrier still faces widespread resentment from its employees and difficult financial fundamentals for its segment of the airline industry.

The opposition to the airline cost-cutting efforts among the work force could get a boost from a published report Thursday that top executives were winning special bonuses and pension guarantees from the airline, even as they were demanding sacrifices from the rank-and-file employees.

Nearly half of the airline's unionized employees voted against concession pacts despite support for the agreements from union leadership and threats of deeper cuts if airline filed for bankruptcy.

Wednesday evening, its flight attendants union rank-and-file reversed their narrow "No" vote to approve a six-year labor pact designed to save the Fort Worth, Texas-based airline $340 million a year in labor costs. The members of the Association of Professional Flight Attendants voted 53 percent in favor of the pact, the day after an initial tally of the vote went 51 percent against the agreement.

The vote marked the third time in less than a month that American had been on the verge of filing for bankruptcy court protections from its creditors, only to avoid a filing due to actions of its unions. But the airline admits it still has a difficult financial outlook ahead of it.

Shares of American Airlines parent AMR Corp. (AMR: Research, Estimates) gained 37 cents to $4.60 in pre-market trading on Instinet Thursday. Shares had gained 83 cents, or 24 percent, to close regular-hours trading Wednesday at $4.23 on investor anticipation that the second vote would be successful at holding off bankruptcy.

American should see a total of $1.8 billion in annual labor cost savings from the agreement with the flight attendants, coupled with the deals approved Tuesday by the other unions.

After the flight attendants' vote, AMR CEO Donald Carty called the concessions from the three unions "unprecedented in the history of the U.S. airline industry."

"This has been a race against the clock," said a statement from Carty. "My thanks go to the union leadership and to all our employees who recognized the urgency of our financial crisis and rose to meet the challenge."

But while demanding deep sacrifices from rank-and-file union employees, the airline was building in some guarantees for its top executives, according to a report in the Wall Street Journal Thursday.

The paper reports that AMR funded a supplemental pension trust for its top 45 executives that protects a portion of their retirement income in the event of a bankruptcy filing. It also gave its top six executives "cash retention" bonuses equal to twice their base salaries to insure that they stay with the carrier through January 2005. A seventh executive will get 1.5 times his base pay as a retention bonus. The bonuses are to be paid in January 2004 and 2005.

The airline told the Journal that most of the pension for its executives would be at risk in case of a bankruptcy, and that the supplemental pension that is protected is similar to protections in place for its pilots. It said that union leadership had been briefed on the various executive pay programs before the votes.

Tuesday had been the deadline the airline set for all three of its unions to have rank-and-file ratification of concession contracts reached March 31, when the airline faced its first bankruptcy deadline. But the union leadership, which had recommended the agreement to members as a way of avoiding bankruptcy, convinced management to extend its original deadline to file for bankruptcy. Two of the unions -- the Allied Pilots Association and Transport Workers Union, which represents most of American's ground workers -- did approve their deals by the deadline.

The leadership of the three unions had only reluctantly endorsed the deals, arguing to their members that work conditions would be even worse if the airline followed through on its threat to file for bankruptcy.

"This was obviously a very difficult decision for our members," said a statement from APFA President John Ward after Wednesday's vote. "None of our members are happy with the situation. However, in the end, the choice came down to deciding between bad and worse."

"No one is naive to the fact that difficult times lie ahead for our members and our company," the statement continued. "The hope is that with the three restructuring agreements now ratified, management can bring our company back from the brink and return it to profitability. Time will tell."

Even with the new labor agreements, American admitted it faced a difficult financial road ahead, and that it might still be forced to seek bankruptcy court protection if it can't negotiate new agreements with lenders and suppliers.

Wednesday's statement from Carty cautioned that even with ratification of the agreements, American's financial condition "is weak and its prospects remain uncertain." The company said it is trying to win "accommodations" from its lenders and suppliers.

"The success of our efforts is not assured," Carty said.

The company's outside auditor, Ernst & Young, said in a Securities and Exchange Commission filing Tuesday that the company's current financial condition is tenuous enough to "raise substantial doubt about the company's ability to continue as a going concern."

The major airlines that operate a large network of hubs serving extensive locations to accommodate business travelers have been having trouble supporting the costs of those systems for more than two years, as demand for business travel -- and the fares those travelers were willing to pay -- fell.

Increased competition from lower-cost, low-fare carriers, such as Southwest Airlines and JetBlue Airways, is causing significant problems for the so-called network carriers such as American.

American Airlines competitor United Airlines, the world's No. 2 airline, filed for bankruptcy protection in December, and US Airways Group, the No. 7 airline, filed for bankruptcy protection in August, although it emerged from bankruptcy at the end of last month.

Neither AMR nor most of the other major network carriers have reported a profitable quarter since 2000, nine months before the Sept. 11 terrorist attacks caused a sharp drop in demand for travel and further financial problems.

Last month's U.S. attack on Iraq also caused further erosion in demand for air travel, particularly on international routes. Concerns about a deadly virus carried by some airline passengers -- severe acute respiratory syndrome (SARS) -- is also hurting demand for air travel, particularly on trans-Pacific routes.

Still, some leading airline analysts said Wednesday that while American still faces a very challenging business environment, the union's new pay packages give it a good chance to stay out of bankruptcy.

Philip Baggaley, the managing director for airlines and aerospace companies at credit rating agency Standard & Poor's, said that the agreements give American immediate cost savings as soon as next month. He said the airline also has a stronger cash position than United did when it filed for bankruptcy protection.

Ray Neidl, airline analyst for Blaylock & Partners, also thinks that AMR can keep flying without seeking protection from creditors.

"That's a lot of costs they're taking out of the system," he said. "I know some folks disagree with me, but I think they stay out of bankruptcy with these deals, unless SARS goes crazy in this country or there's another terrorism attack."