About 1 million Americans a day packed airports and planes over the weekend even as coronavirus deaths surged across the U.S. and public health experts begged people to stay home and avoid big Thanksgiving gatherings.

And the crowds are only expected to grow. Next Sunday is likely to be the busiest day of the holiday period.

To be sure, the number of people flying for Thanksgiving is down by more than half from last year because of the rapidly worsening outbreak. However, the 3 million who went through U.S. airport checkpoints from Friday through Sunday marked the biggest crowds since mid-March, when the COVID-19 crisis took hold in the United States.

Many travelers are unwilling to miss out on seeing family and are convinced they can do it safely. Also, many colleges have ended their in-person classes, propelling students to return home.

Laurie Pearcy, director of administration for a Minneapolis law firm, is flying to New Orleans to attend her daughter’s bridal shower and have a small Thanksgiving dinner with her son.

“I don’t want to unknowingly make anyone sick. But I also don’t want to miss this special event for my only daughter,” she said.

Stephen Browning, a retired executive from Tucson, Arizona, will be flying to Seattle for Thanksgiving with his sister. The celebration usually has up to 30 people; this year only 10 are coming, and everyone was asked to get a coronavirus test. He doesn’t plan on removing his mask to eat or drink on the flight.

“This is my first flight since December 2019, so yes, I have concerns,” he said. “But I think most airlines are acting responsibly now and enforcing masks on all flights.”

Last week, the Centers for Disease Control and Prevention urged Americans not to travel or spend the holiday with people outside their household.

New cases of the virus in the U.S. have rocketed to all-time highs, averaging more than 170,000 per day, and deaths have soared to over 1,500 a day, the highest level since the spring. The virus is blamed for more than a quarter-million deaths in the U.S. and over 12 million confirmed infections.

“There is so much community transmission all over the United States that the chances of you encountering somebody that has COVID-19 is actually very, very high, whether it’s on an airplane, at the airport or at a rest area,” said Dr. Syra Madad, an infectious-disease epidemiologist for New York City hospitals.

The nation’s top infectious-diseases expert, Dr. Anthony Fauci, told CBS’ “Face the Nation” that people at airports “are going to get us into even more trouble than we’re in right now.”

The message may be sinking in for some.

Bookings in 2020 are down about 60% from where they were this time last year. Thanksgiving reservations were ticking upward in early October but fell back again as case numbers surged. Since airlines have made it easier to cancel tickets, there could be a rash of cancellations closer to the holiday, said John Elder, an adviser to airlines from Boston Consulting Group.