Americans took to the skies in large numbers over the weekend despite warnings from the Centers for Disease Control and Prevention to stay home for the Thanksgiving holiday to help prevent further spread of the coronavirus.

More than 3 million people passed through security checkpoints at U.S. airports from Friday through Sunday, according to the Transportation Security Administration. 

While those numbers are less than half of what they were a year ago, Friday and Sunday accounted for just the second and third times since the pandemic began when more than 1 million people were screened in a day. 

A video shot Friday inside Phoenix Sky Harbor Airport showed passengers crowding around gates. 

"This is about as crowded as it was before COVID hit," said Ed Westerfield, who shot the video, said, according to AZFamily.com. "This is just jam-packed."

On Thursday, the CDC issued guidance urging people not to travel for the holiday. 

“We’re alarmed,” Dr. Henry Walke, the CDC’s COVID-19 incident manager, said during a news conference. “What we’re concerned about is not only the actual mode of travel — whether it’s an airplane or bus or car, but also the transportation hubs we’re concerned about, as well.”

The public health agency also recommended that people, even if they do not leave town, avoid celebrating Thanksgiving with those from other households. 

"The tragedy that could happen is that one of your family members is coming to this family gathering and they could end up severely ill, hospitalized or dying,” Walke said. “And we don't want that to happen. These times are tough, it's been a long outbreak, almost 11 months, and we understand people are tired."

“We understand that people want to see their family and relatives and do it as they’ve always done it," he added. "But this year we’re asking them to limit their travel.”

The U.S. surpassed 12 million coronavirus cases over the weekend and has recorded more than 256,000 deaths from COVID-19, according to data compiled by Johns Hopkins University. On Friday, the country set a new record with 196,004 new cases. Nearly 84,000 people are currently hospitalized with the virus, more than at any other time during the pandemic, according to The COVID Tracking Project.

Dr. Anthony Fauci, the federal government’s top infectious disease expert, on Sunday echoed the CDC’s concerns about Thanksgiving travel.

“Sometimes when you get a crowded plane, you're in a crowded airport, you're lining up, not everybody's wearing masks, that puts yourself at risk,” he told CBS’s “Face the Nation.” “One of the things we're really concerned about is that as we get into this Thanksgiving season, you're not going to see an increase until weeks later. Things lag. So what you don't want to see is another spike in cases as we get colder and colder into the December and then you start dealing with the Christmas holiday. We can really be in a very difficult situation.

“So you want to tell people to please seriously consider decisions that you make.”