December 1 might seem like an arbitrary date to expect a large number of passengers. However, this year, December 1st marks the end of the Thanksgiving holiday period.
December 1st, however, is going to see the most number of passengers with 3.1 million expected on that day alone. 2.98 million passengers are expected to travel on Wednesday, November 27th. However, Thanksgiving day itself will see only 1.79 million passengers. Compared to last year, the Thanksgiving travel period will see a 3.7% increase in the number of travelers over the period, an extra 859 more flights per day with over 108,000 extra seats per day, and, finally, an additional 93,000 daily passengers.
Collected and summarized from the source below by Ta Ngoc Diep: https://simpleflying.com/december-1-travel/