Winter blizzard grounded 6,000 flights By: MarketWatch January 13, 2011 at 14:27 PM EST Snow and freezing rain hammered U.S. airlines this week, forcing airlines to cancel more than 6,000 flights, a bruising start to the first quarter. Read More >> Related Stocks: Alaska Air Group Allegiant Travel Com Copa Holdings S.A. Delta Air Lines Hawaiian Hlds Inc