US airlines are offering travel waivers with a bomb cyclone winter storm bearing down on the Midwest.
Chicago is expected to be hit hard, the National Weather Service warns.
Many airlines are permitting limited time changes to tickets for free.
Chicago based United Airlines is offering waivers for flights in the Midwest, Texas, the East Coast and for Central and Northwest United States.
Change fees and fare differences will be waived .
Delta and American Airlines announced similar travel waivers for various regions.
The bomb cyclone storm is expected to pass through the Midwest, Northeast and South through the end of this week.
Snow, high winds and extreme cold are expected.
It will also affect Amtrak services.
Winter storm alerts were posted for Chicago, Detroit, Indianapolis, Kansas City and other cities.
