NEW YORK (AP) — Memories of the Valentine's Day ice storm that grounded more than a thousand JetBlue flights and tens of thousands of passengers did not stop Suzanne Dohm from flying the New York airline.

"One incident like that is not going to turn me off. Those were extraordinary circumstances," said Dohm, of New York, while waiting on a recent day for a JetBlue flight at John F Kennedy International Airport. "I know what it was like that day. It was horrible."

Customers may be willing to forgive the airline that offers free snacks and DirecTV at every seat, but investors have not: Shares of JetBlue Airways have been on a long slide in recent months and now trade for little more than half their January peak.

One big concern is that JetBlue has been forced to scale back its growth plans as it faces new competition from startup Virgin America and other carriers. Wall Street analysts say the seven-year-old carrier's high debt load, along with its chronically congested JFK hub and reliance on cutthroat domestic routes, are crimping profits and leave it vulnerable to a takeover.

Indeed, JetBlue's revenues per available seat mile have grown only 9.4 percent over the last five years, compared to growth rates of 23.5 percent at Southwest Airlines Co. and 28.6 percent at AMR Corp., which operates American Airlines. Per-seat costs, meanwhile, have jumped 29.4 percent at JetBlue, compared to a 20.7-percent increase at Southwest and a 3.3-percent increase at AMR. Fuel expenses, which make up nearly a quarter of airline costs, have risen sharply in recent years. Labour expenses have also increased, though more slowly.

JetBlue's new management team knows that boosting the airline's financial performance is imperative. But they also have no choice but to keep their focus on operational issues. Another systemwide mis-step could be fatal.

JetBlue made headlines in February when an ice storm that socked the Northeast collided head on with the carrier's policy of not canceling flights ahead of bad weather. JFK was particularly hard-hit as planes continued to arrive and none were allowed to leave. Thousands of people were trapped on planes for hours or stranded in terminals for days.

"We gridlocked ourselves," said Dave Barger — named chief executive in May when JetBlue's board asked founder David Neeleman to step down.

Neeleman, who remains chairman, was criticised for spending more time apologizing than fixing problems. JetBlue did not fly a full schedule for days.

Over the next month, JetBlue implemented a pre-cancellation policy and a "remote exit" procedure to get passengers off planes when terminal gates are full. It hired operational experts, including chief operating officer Russell Chew, who has an airline and Federal Aviation Administration background.

Most visibly, JetBlue drafted a "customer bill of rights," promising vouchers in some cases when passengers are stranded or delayed. Vouchers cost the company $24 million in the first quarter, which included the storm. JetBlue has not disclosed its voucher costs since.

While the changes didn't save Neeleman, they helped JetBlue avoid a second meltdown when another ice storm struck on March 16. "We pre-cancelled the airline and the next day we were at (a) 94 percent completion factor," Barger said. "That was a textbook event."

Customers continue to be loyal. JetBlue topped consumer surveys by J.D. Power and Associates and Consumer Reports conducted since the February storm.

"They don't treat you like you're an idiot or just a piece of cattle," Dohm said.

JetBlue helped itself by taking immediate responsibility and changing quickly, said Tom O'Guinn, a marketing professor at the University of Wisconsin and executive director of the Center for Brand and Product Management. "They were very contrite. I think that helped a lot," he said.

Barger acknowledges that the storm problems cost JetBlue some bookings. But he adds, "what we heard from customers was, 'OK, thanks for the apology. Stop apologizing. Fix it, and we really like you guys. Make sure it doesn't happen again.' "

That's a tough task, however, when your home base is JFK airport, where summer storms and overloaded skies contributed this summer to one of the nation's worst on-time showings.

In June, JetBlue flights were on time (defined as arriving within 15 minutes of schedule) only 63 percent of the time, compared to an industry average of 69.4 percent, according to Flightstats.com. Things did not get much better in July, when JetBlue flights were on time only 65.3 percent of the time, compared to an industry average of 71.5 percent.