More than 1,000 flights have been cancelled as winter weather wreaks havoc on some of the US' busiest airports

AP Photo/Noreen Nasir

Crews de-ice an American Airlines plane at O'Hare International Airport

• A frigid polar vortex is wreaking havoc on air travel at some of the nation's busiest airports, including Chicago and Atlanta.
• More than 1,000 flights were canceled by 9 a.m. Tuesday, adding to the hundreds more disrupted on Monday.
• Many airlines have waived change fees for customers flying through affected airports.

More than 900 flights were canceled Tuesday morning, adding to the more than 1,000 disrupted on Monday, as winter weather from Chicago to Boston and Atlanta wreaks havoc on air travel.

At United's Chicago hub, where the National Weather Service predicts a high temperature of 5 degrees on Tuesday with frigid windchill extending well into the negatives, more than 150 flights were canceled by 9 a.m., according to FlightAware.

"We expect to operate on a reduced schedule throughout the week," United spokesperson Robert Einhorn told Business Insider. He also noted that the airline is coping with the storm by adding additional ramp workers at O'Hare so that employees may work shorter shifts in the cold, as well as moving some equipment inside away from the elements.

Across town at Midway, Southwest's largest hub, things were just as bleak, with more than 250 flights canceled as of 9 a.m. Tuesday. Those travel headaches will only compound the delays from Monday, when 1200 flights were cancelled, according to the USA Today.

Southwest Airlines said through a spokesperson that "customers will see flight reduction due to weather," mostly in Chicago and Milwaukee.

Read more: The frigid 'polar vortex' cold snap engulfing the US is so bad it can give people frostbite in 5 minutes

"Wintry precipitation could delay flights today from Boston (BOS) to Atlanta (ATL), as well as in Chicago (MDW, ORD)," The FAA's daily air traffic report said Tuesday morning. "Low clouds are expected this morning in San Francisco (SFO). Super Bowl traffic into the Atlanta area is expected to increase today."

Super Bowl flights could be disrupted

In Atlanta, where traffic for the Super Bowl is expected to begin hitting the nation's busiest airport today, Delta Air Lines said it had proactively canceled "approximately 170 mainline and Delta Connection flights" due to snow and icy conditions.

The National Weather Service's winter weather advisory for rain, snow and black ice in Atlanta is in effect until 7 p.m. tonight

There were also scattered delays in New York City, Boston, and Washington DC due to wind, rain, and snow.

If you're traveling today and need to make changes, many carriers have waived change fees for affected airports. Check with your specific airline here:

• Southwest
• United
• Delta
• American

Read Business Insider's full coverage of winter storm Jayden and the related polar vortex here.