United has canceled 22,500 flights so far this year.
That was four times as many canceled flights for United as during the first two months of last year.
United disclosed the number of cancellations Thursday night and said its revenue would suffer as a result.
Shares of United Continental (Fortune 500) were down 3% in premarket trading Friday. ,
Shares of Delta Air Lines (Fortune 500) were also down -- Delta is the No. 3 airline behind , American Airlines Group ( and United. )
Chicago-based United Continental was not the only airline with weather problems, but with major hubs in Chicago and Newark, it has been hit particularly hard.
Through the first six weeks of the year, flight tracker masFlight estimates that there were 75,000 canceled flights at U.S. airlines, the largest number since U.S. airspace was shutdown following the Sept. 11 terrorist attack.
JetBlue Airways (Fortune 500), which operates 45% of its flights through New York or Boston, has also been hit hard. It warned in early January that 1,800 canceled flights the first week of the year would cost it $45 million in revenue and $30 million in profits. ,
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