Transcript for Millions Travel During the Busy Thanksgiving Holiday
It's getting cold here tomorrow. The weather cause D disruptions for holiday travel. David Kerley is at Reagan national with the latest. Reporter: Good morning, George. Airports will be busy. Just shy of 2.5 million people will fly today. Almost as many as yesterday, some still trying to get back home. Some going back to work. Talk to anybody at Chicago's midway airport yesterday, and you will hear a horror story. This morning, another busy travel day after the holiday with hopes this is not repeated. This is a security line. Reporter: A mess at Chicago's midway Sunday, not caused by snow, rain, or sleet. I've been here a total of seven hours. Reporter: This was a man-made problem on the busiest air travel day of the year. A line that reporter Denise Whitaker described as a mile long. Believe it or not, it was a tsa staffing snafu. Not enough officers assigned to work. It snowballed with people grounded for hours. We missed our flight by one minute. Reporter: 4,000 flights delayed in total, 400 cancelled. Rain in the west. Fog if Denver. If you see the fog bank? Do you see the ground anywhere? You're above it, aren't you? We're above it. We do not see anything. Reporter: Hard to see stuff in the fog. The good news is the weather should cooperate today. And for the Christmas holiday, robin, don't expect a travel week like what we just got through.
This transcript has been automatically generated and may not be 100% accurate.