Wednesday was expected to be the busiest travel day before Christmas at Minneapolis-St. Paul International Airport, and the crowds didn't disappoint.

Passengers converged on Terminal 1 early Wednesday, and security lines snaked through Terminal 2 back to the parking deck. Some 17,000 people in all were expected to be screened by the Transportation Security Administration (TSA).

Travelers took to the skies despite an advisory from the Centers for Disease Control and Prevention (CDC) to delay travel because it "may increase your chance of spreading and getting COVID-19."

The advisory added: "CDC continues to recommend postponing travel and staying home, as this is the best way to protect yourself and others this year."

Travel industry analyst Henry Harteveldt, president of San Francisco-based Atmosphere Research Group, said that "people are traveling because they want to, and because they are suffering 'COVID fatigue.' "

Harteveldt said they've "tuned out the guidance from CDC, other public health organizations and elected officials. Visiting family or friends, or taking a vacation, is important to these travelers."

However, Wednesday's blizzard likely contributed to nearly 300 flight cancellations and 48 flights delayed at MSP by late afternoon.

The busiest overall travel day for the holiday season is expected to come Sunday, with some 19,000 passengers likely to be screened at MSP's two terminals, according to Patrick Hogan, spokesman for the Metropolitan Airports Commission (MAC), which operates MSP.

"We expect peak travel during the Christmas holiday to mark the busiest days since April," Hogan said. "Even so, crowds will be less than half what they were last Christmas.

"Our primary focus is on keeping those who choose to travel as safe as possible, requiring masks and encouraging social distancing and frequent hand sanitizing," he said. "People who haven't traveled since last Christmas will see a lot of changes at the airport, including plexiglass shields where they interact closely with airport workers, to try to keep the holiday as healthy as it is happy."

Since last Friday, the TSA has screened nearly 5 million passengers nationally, including 1 million passengers on Friday, Saturday and Sunday.

The last time passenger numbers topped the 1 million mark nationally was on the Wednesday and Sunday bracketing the Thanksgiving holiday weekend.

Hogan said the high mark for Thanksgiving screenings was Nov. 25, with 15,383 people screened at MSP checkpoints. The busiest day for Thanksgiving last year was the following Sunday, with some 43,821 passengers screened at MSP.

The pandemic has savaged air travel. Christmas passenger volume at MSP is down 55 to 65% this year when compared with 2019, Hogan said.

MSP requires that passengers wear masks and practice social distancing.

"Undoubtedly, these travelers would tell you that they will be careful and responsible during their journeys," Harteveldt said, "and I hope they will be."

Some of them, he said, may use the availability of lower prices for airfare, hotels and rental cars "to help justify their decisions to travel."