Airlines are offering to waive fees for tickets over the Thanksgiving period as another powerful snowstorm threatens to snarl the travel plans of millions traveling home from the holiday.

Travelers returning from spending the Thanksgiving weekend with loved ones face massive cancellations and delays on Sunday as a storm marches eastward from California, according to CNBC.

Delta Air Lines has offered to waive change fees from passengers on flights on Sunday and Monday from more than 20 airports including New York’s LaGuardia, Newark, and JFK.

American Airlines has issued a similar reprieve for 29 airports including Boston, Pittsburgh, and New York.

A large storm is expected to move eastward from California to New York, dumping heavy snow and creating blizzard conditions in the Upper Midwest and Great Lakes, the National Weather Service said.

The storm system will also bring freezing rain and sleet in Pennsylvania and New York from Sunday into Monday.

Two large storm systems also plunged Thanksgiving travel plans into chaos last week — canceling thousands of flights, closing highways and dumping up to 30 inches of snow.