ORLANDO, Fla. -

Airlines have started cancelling flights scheduled in and out of the Northeast as the region braces for another big weather event just a week after Hurricane Sandy.  A classic Nor'easter, a messy mix of snow and rain, is forecast for parts of the Mid-Atlantic and New England today and tomorrow.

United Airlines is grounding about 500 flights between noon Wednesday and noon Thursday out of Newark Liberty, John F. Kennedy International and LaGuardia airports.   Many United passengers were automatically rebooked on other flights to their destinations.

Other carriers, like Delta, JetBlue, and AirTran are already anticipating cancellations and delays, and are waiving change/cancellation fees on flights to and from several Northeast airports including Boston, New York, Washington, D.C., Hartford, and Philadelphia.

Last week Superstorm Sandy led to more than 23,000 cancellations in the region.

Passengers should contact their airlines directly, or visit the carriers' web sites for complete and current details.