Updated 12/20/12 at 9:00 p.m.

CHICAGO (CBS) — With a snowstorm hitting the northwest suburbs on the way to the Chicago area, hundreds of flights were cancelled at O’Hare and Midway airports, in many cases leaving travelers stranded.

The Chicago Department of Aviation said more than 500 flights had been cancelled at the two airports as of 8:30 p.m.

Among the snake-bitten travelers at O’Hare were members of the Odeh family from Roscoe, Ill. On Thursday, they were trying to make a flight to Miami to catch a cruise ship Saturday – but no such luck.

Their airline said they could get seats for a Monday flight, but that would be after their ship set sail from Florida. The family opted to drive the 1,500 miles, CBS 2’s Mike Parker reports.

Southwest Airlines said it was cancelling its entire schedule of flights departing Midway International Airport starting at 4 p.m. Thursday. Spokesman Brad Hawkins said the airline made a pre-emptive decision to prevent passengers from being stranded at the airport after the brunt of the storm hits the city.

“We don’t want people traveling to the airport to stand in line, when we know that we’re probably not going to be able to provide the best customer service experience, or safely operate the aircraft,” he said. “Be patient with us. Fortunately, this storm is moving quickly.”

Hawkins said most arriving Southwest and AirTran flights should still make it into Midway, so planes and crews will be in place for a normal schedule Friday morning, after the storm has passed. Southwest and AirTran are in the process of merging operations nationwide under the Southwest label.

At O’Hare, American Airlines spokeswoman Mary Frances Fagan said all domestic flights scheduled after 8 p.m. have been cancelled.

As of 8:30 p.m., airlines at Midway were reporting a relative handful of delays, but more than 150 cancellations.

At O’Hare International Airport, airlines were reporting more than 350 cancelled flights. Airlines at O’Hare also were reporting delays of between 30 and 40 minutes for arriving and departing flights. The city’s aviation department planned to set out cots and provide “amenity kits” to stranded travelers after 9 p.m. Thursday, spokeswoman Karen Pride said.

Anyone using either airport on Thursday should check with their airline to check the status of their flight before leaving for the airport.

With the Christmas and New Year’s holidays coming up, Friday is expected to be the busiest travel day at both airports. City Aviation officials said about 200,000 passengers are expected to fly through O’Hare on Friday, with another 66,000 passengers at Midway.

Although temperatures are not expected to rise above freezing on Friday, the snow should have ended by early Friday morning, with skies clearing for the afternoon and evening.

In all, an estimated 2.4 million passengers will travel through O’Hare and Midway between Dec. 21 and Jan. 2.

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