American Airlines, the world’s largest carrier, said winter storms that grounded flights reduced first-quarter revenue by about $115 million and operating profit by about $60 million.

Operating margin for the three months that ended March 31 will be 5 percent to 7 percent, below the airline’s January forecast of 6 percent to 8 percent, the Fort Worth, Texas-based carrier said in a statement today.

Harsh snow, ice and frigid weather that battered large swaths of the country, especially American’s hubs in Charlotte, North Carolina, Chicago, Dallas and New York, forced the airline to cancel more than 34,000 flights, it said. The four biggest U.S. airlines in total were forced to cancel more than 74,000 flights in the first two months of this year.

Passenger unit revenue, or revenue from each seat flown a mile, will rise 2.5 percent to 3.5 percent, within a forecast of 2 percent to 4 percent provided by American on March 10.

To contact the reporter on this story: Mary Schlangenstein in Dallas at To contact the editors responsible for this story: Ed Dufner at Molly Schuetz, James Callan.

Photo Credit: American Airlines Boeing 777 rotates off the runway at Chicago O'Hare enroute to Shanghai. T.J. Van Haag / Flickr