CHICAGO -- Traffic Friday is expected to exceed pre-pandemic levels.
AAA estimates more than 48 million Americans will take at least one trip over the holiday weekend, ABC News reported.
One expert warned Friday could look more like the day before Thanksgiving than early July.
On Thursday, TSA said it screened 2.1 million people.
Millions across the country are preparing to celebrate America's independence and the country's reopening.
And O'Hare airport had a somewhat unexpected early surge of travelers Friday morning. That's only expected to increase as the day goes on.
"I was expecting it to be busy because of July 4th weekend but not as busy because of COVID," Anthony Crump said.
At Midway, over 200,000 passengers are expected, an increase of 77% over last year.
Brian Fay and his family made extra time for the drive to the airport and it worked.
"I was expecting it to be crowded, but it was pretty straightforward and no traffic, so," Fay said.
But the travel rush is already off to a rocky start, as airlines cancel flights due to bad weather and a post-pandemic worker shortage.
American Airlines canceled 13 flights in and out of Charlotte this week, reportedly because they had no crew to fly the planes, frustrating a traveler who missed her connecting flight.
"I'm tired, I'm cranky, I'm hungry," she said.
Southwest Airlines canceled or delayed thousands of flights across the country last weekend, partially blaming weather and also a pilot shortage.
Pilots blame the airlines for not being prepared, after laying off thousands of employees during the pandemic, even while getting billions of dollars in COVID-relief funds from the government.
"It's 12-15 months once you lay a pilot off to get the whole operation running again," said Dennis Tajer with the Allied Pilots Association. "A year ago, we were canceling flights because we didn't have enough passengers, and now we're canceling because we don't have enough pilots. How did that happen? That's unacceptable."
And when it comes to traffic AAA said drivers on Highway 17 near San Francisco can expect congestion to be 340% worse than usual.
It'll be about the same on I-95 near Boston - 330% worse than usual, experts said.
"People should be expecting that the empty roads of the past year are kind of over," AAA spokesperson Andrew Gross said.
Most Americans are expected to travel by car this weekend, just as gas prices hit a seven-year high. It's now averaging $3.12 a gallon nationwide.
Those driving outside Illinois this weekend should consider filling up outside the state, after Illinois' gas tax increased Thursday.
Traffic tracking company INRIX said the best time to hit the road this weekend is Friday morning or Saturday after 2 p.m. The worst traffic will likely be on eastbound Interstate 90 from West Roosevelt Road to the Tri-State.
The worst time to travel will be between 4 and 6 p.m. Friday.
ABC 7 Chicago contributed to this report.