NEW YORK (CNN/Money) - Southwest Airlines, the only major U.S. air carrier to remain profitable since Sept. 11, could have its first money-losing quarter in more than a decade if the U.S. engages in a protracted war with Iraq, according to the company's chief executive.

Jim Parker, CEO of the successful low-cost, low-fare airline, told CNN/Money that there are too many variables to say for certain what the profit outlook for his airline would be. But he said the airline's almost unique ability to stay in the black following the Sept. 11 attack does not mean it is immune to the effects of a new Gulf War.

"It's hard to predict without knowing how extreme the drop-off of traffic will be, how high fuel costs would go, how long they would stay there," he said. "Our hope is to continue a record of profitability. But we're not war-proof, we're not recession-proof, we're not 9/11-proof."

Still the carrier, the nation's No. 6 airline, was able to make money throughout the first eight months of 2001, when a slowing economy and drop in high-priced business travel plunged most major airlines into deep losses.

"We used to say we're not recession-proof, we're recession resistant, because of our lower cost structure," he said. "Our whole business model is built on carrying people for affordable fares. In difficult economic times, that's an advantage. Even in normal times, people care what things cost. It was kind of unusual when we went through a period in the late 1990s when a large number of business travelers didn't care what things costs."

In the wake of the Sept. 11 attack, Southwest was the only carrier among the nation's 10 largest airlines to report a profit in the fourth quarter of 2001. And it has continued to post profits through 2002. Outside of Southwest, there have been only a handful of profitable quarters by any publicly held carrier since the attack.

Related stories Attack of the low-fare airlines Southwest 2Q profits fall, warns Big people pay more

But a large rise in the cost of fuel that could come with a second Gulf War would hit Southwest as well as other airlines. The fall in fuel prices following Sept. 11 helped mitigate losses elsewhere in the industry and helped maintain profitability at Southwest. Fuel was about 15 percent of the company's overall operating expenses in the third quarter, its second largest cost behind labor.

Southwest last reported a loss in the first quarter of 1991, when the first Gulf War took place and fuel prices briefly skyrocketed while air travel fell. It returned to profitability the next quarter, though, and it has never had a money-losing year in its 32-year history.

Analysts surveyed by earnings tracker First Call forecast the company will earn 3 cents a share in the current quarter, compared with the 4 cents a share it earned a year earlier. It is also expected to earn 3 cents a share in the first quarter of 2003, the same as a year earlier, and then post earnings per share in each successive quarter that are better than results in the comparable 2002 period. The consensus EPS forecast for 2003 is for 46 cents a share, up from the 22-cent forecast for 2002 EPS.

Shares of Southwest (LUV: up $0.04 to $15.22, Research, Estimates) were little changed in Tuesday trading.