American Airlines has canceled an additional 300 flights as the threat of a heavy winter storm threatened many locations across the U.S.

The additional cancelations comes after 650 combined flights were canceled by AA and American Eagle this weekend, according to flight-tracking site FlightAware.com.

Click here to see the flights canceled.

Over 43 million people are expected to travel 50 miles or more for Thanksgiving. People have been warned not to drive during the worst conditions, expected to occur on Nov. 26 or Nov. 27, according to Kevin Roth, lead meteorologist at The Weather Channel.

"The worst is going to come on Tuesday and run into Wednesday, so if people traveling can get out before then, or wait until afterward, that would be the best thing," said Roth.

Three million travelers are expecting to commute by plane, but there plans might have to change.

The storm has already dropped a foot of snow in Utah and Colorado, and has claimed 13 lives.

The cancelations could mean bad news for thousands of people looking to fly somewhere for the Thanksgiving holiday.

The storm is expected to move east and affect operations at some of the busiest airports in the U.S. just days before Thanksgiving.

American and American Eagle are both hoping to continue normal operations no later than Nov. 26.

Approximately 12 inches of snow is expected to fall in Buffalo and Syracuse, N.Y., and up to 8 inches has been predicted for Pittsburgh.

See Now: OnePlus 6: How Different Will It Be From OnePlus 5?