U.S. airlines have waived their rebooking fees as winter weather struck the Chicago area today and threatens the Northeast as the Thanksgiving travel season approaches.

With snow falling at Chicago’s O’Hare International Airport, United Continental Holdings Inc. waived its customary fee for flight changes today for travel into, out of or through O’Hare. United spokesman Charles Hobart said the airline experienced more delays than normal because of the winter weather, but had only six cancellations at O’Hare at its mainline and regional flights.

All told, O’Hare had about 125 cancellations as of 5 p.m. in Chicago. An airport spokeswoman said that isn’t an unusually high number.

American Airlines Group Inc. and Delta Air Lines Inc. waived change fees for flights out of 18 and 19 airports, respectively, in the Northeast. American’s waiver applies to travel on Nov. 26 and allows travelers to rebook flights from tomorrow through Nov. 27. Delta’s waiver also applies to travel on Nov. 26 and allows for rebooked flights starting no later than Nov. 28.

The six-day Thanksgiving holiday period, from tomorrow through Nov. 30, is the among the busiest travel times in the U.S. Air passengers are expected to rise to the highest level since 2007, totaling 3.55 million, a 3 percent increase from a year earlier, according to AAA.

A storm is expected to dump as much as 6 inches of snow across northern portions of New York City on Nov. 26. Lower Manhattan could see 2 to 4 inches, the National Weather Service said. A winter storm watch is in effect for Nov. 26 to Nov. 27 in parts of Virginia, New Jersey, Pennsylvania, Massachusetts and Connecticut, the weather service said.

To contact the reporter on this story: Michael Sasso in Atlanta at msasso9@bloomberg.net. To contact the editors responsible for this story: Ed Dufner at edufner@bloomberg.net.

Photo Credit: Flight information including delays are on display on a screen at the Washington Dulles Airport in Dulles, Virginia. Hyungwon Kang / Reuters