Airlines cancel 600 more flights but disruptions from winter storm ease

* Airlines canceled 600 U.S. flights on Saturday after more than 1,700 cancellations Friday amid a large winter storm that hit Northeast U.S. on Friday.

* American, Delta, Southwest and other airlines waived change fees and fare differences for customers.

* The storm is putting airlines to the test during what they expect will be a record end-year holiday travel season.