CHICAGO – Andrew Sobotka was delayed five hours last week on a flight back to Chicago from Las Vegas, where he and his hockey teammates were celebrating the team captain’s birthday. Because of the delay, he and several teammates of the Chicago Gay Hockey Association didn’t get home until 4 a.m., he said.

“A major inconvenience,” he said. “Obviously, everyone has to go to work the next day.”

Sobotka, 26, of Chicago said he received a compensation travel voucher only after he stopped phoning customer service and started contacting the airline on Twitter.

“Once I use my voucher, I’ll try not to fly American Airlines,” he said.

Ongoing flight delays and cancellations at American Airlines are taking a toll on the company and its passengers nationwide as the airline entered a third week of operational slowdowns, which it blames on a labor dispute with its pilots over wages, benefits and working conditions. Would-be passengers, especially business travelers, are likely defecting from the carrier and booking on other airlines to avoid potential hassles, experts say.

“People are already booking on other airlines. . It’s starting to increase exponentially,” said Gene Grabowski, executive vice president of Washington, D.C., communications firm Levick, which has counseled airlines in managing their reputations. “If this goes on for another couple of weeks, it could really damage the brand, massively.”

AMR Corp.-owned American Airlines, which is currently in bankruptcy protection, has been ravaged by operational problems in recent weeks. Since Sept. 16, barely half of its flights have been on time, while other major airlines collectively were on time about 87 percent of the time, according to data from FlightStats.com. Since then, American has canceled more than 900 flights and experienced nearly 13,000 delays nationwide, far more than any other major airline.

The airline has said it will reduce its flying by up to 2 percent through October to compensate for more pilots calling in sick. Sick rates in September were up 21 percent over the previous September, an airline spokesman said.

Chris Salinas, 39, of Chicago was at Chicago O’Hare International Airport on Monday waiting to travel to Louisville, Ky., on business. He said he travels three or four times a year and felt obligated to use American Airlines because he earns frequent-flier miles on the airline.

Even though his flight had not been delayed or canceled as of 2 p.m., Salinas said he will consider using other airlines because of American Airline’s labor strife. “I will switch whenever I have the chance,” he said.

AMR Corp. blames the delays and cancellations on disgruntled pilots who have dramatically increased the number of maintenance reports they have filed, which holds up flights because the problems must be addressed before takeoff. AMR has said some of the write-ups have been for such issues as broken coffee pots, nonfunctioning passenger reading lights and torn seatback pockets.

But the pilots union, the Allied Pilots Association, said it has not sponsored a coordinated effort to harm the airline and that the write-ups are increasing because American isn’t adequately maintaining its aged fleet of planes. Pilots also have denied organizing a sick-out and dispute that pilots are using any more sick time than usual.

“We’re tired of it too, and we want to see it corrected,” said union spokesman Dennis Tajer. “Our pilots continue to be the last line of defense for our passengers’ safety, and we take that very seriously.”

As part of its bankruptcy restructuring, AMR recently imposed severe pay and benefit cuts on pilots, although it has offered to restart negotiations to strike a labor deal.

Accusations fly back and forth almost daily, but the source of American’s operational problems is clear, said Henry Harteveldt, an airline industry researcher with Atmosphere Research Group. “There’s no question, the pilots are engaging in business sabotage,” he said, adding that he hasn’t seen such a severe labor war in the industry since an Eastern Airlines mechanics strike in 1989.

Tajer, the pilots union spokesman, said it’s not true that pilots are sabotaging the airline.

American Airlines concedes it is hurting. The recent operational problem “is inflicting economic damage on the company; it is frustrating and alienating our customers,” wrote Denise Lynn, senior vice president of people at American Airlines in a letter to pilots last week threatening legal action against if pilots’ alleged actions persisted. “If this conduct continues, it will diminish the value of the company.”

American spokesman Bruce Hicks said it was too early to quantify what financial impact the operational problems have had.