The late crush of holiday travelers is picking up steam, with about 2.7 million people expected to board flights on Wednesday and millions more planning to drive to Thanksgiving celebrations.

Airline officials say they are confident that they can avoid the kind of massive disruptions that have marred past holiday seasons, such as the meltdown at Southwest Airlines over last Christmas.

Airlines have added tens of thousands of employees in the last couple years, and Southwest says it has bought more winter equipment to keep planes moving even during sub-freezing temperatures.

Security lines at airports could be long because of the crowds. Delta Air Lines is telling passengers to arrive at the airport at least two hours before their flight if they are traveling within the United States, three hours early if they’re flying overseas — and maybe earlier on Sunday and Monday.

The holiday will also test the Federal Aviation Administration, which faces shortages of air traffic controllers at key facilities that caused reductions in flights to the New York City area this summer and fall.

U.S. Transportation Secretary Pete Buttigieg said during a news conference Monday that the government has prepared for holiday travel by hiring more air traffic controllers, opening new air routes along the East Coast and providing grants to airports for snowplows and deicing equipment.

Nearly three-fourths of flight delays are caused by weather, according to the FAA. The agency’s figures indicate that the rate of canceled flights is down this year from last year, when airlines didn’t have enough staff to handle the strong recovery in travel after the pandemic.

The Transportation Security Administration predicts that it will screen 2.7 million passengers Wednesday and a record 2.9 million on Sunday, the biggest day for return trips. That would narrowly beat TSA’s all-time mark set on June 30.

“We are ready for the holidays. We’re confident we have enough agents,” TSA Administrator David Pekoske said Tuesday on ABC’s “Good Morning America.”

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He urged travelers to give themself extra time to get through busy airports and be considerate of TSA agents, gate agents and flight crews and others who are giving up their holidays.

“I just ask passengers to thank people for what they’re doing. They’re making sure the system is safe and secure. That’s a tall order,” he said.

AAA predicts that 55.4 million people will travel at least 50 miles from home between Wednesday and Sunday, the third-highest forecast ever by the auto club. AAA says most of them — 49.1 million — will drive.

Drivers will get a break from last year on gasoline prices. AAA says the nationwide average for gas was down to $3.29 a gallon on Tuesday, compared with $3.66 a year ago.

Air travelers will enjoy lower prices too. Airfares in October were down 13% from last year, according to government figures, and fares around Thanksgiving have been about 14% lower than a year ago, according to the travel site Hopper.

Even so, the high cost of rent, food, health care and other expenses were weighing on people’s travel plans.

Jason McQueary, a 25-year-old social worker and graduate student said rent and other essentials eat up most of his paycheck and he was grateful for his credit card points, which brought down the cost of his roundtrip flight from Denver to Chicago from $450 to $150.

“I was just like, ‘man, I’m glad I only come home once a year,’” said McQueary, who was waiting to get picked up Tuesday after arriving to Chicago O’Hare International Airport to spend Thanksgiving with family in his hometown of Byron, Illinois.