Atlanta -- A day after travelers waited nearly 90 minutes in snail-speed security lines at the world's busiest airport, Atlanta's mayor was concerned Tuesday about the waits that could result when the city hosts the 2019 Super Bowl.

The ongoing partial government shutdown is "uncharted territory" amid planning for one of the world's biggest sporting events, Mayor Keisha Lance Bottoms said.

"Obviously, we are in uncharted territory with the shutdown that's gone on this long, and we are preparing as best we can from our vantage point," Bottoms said.

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The mayor and others at a Tuesday news conference said two years of planning have them well-prepared to protect the public.

"Our goal is for our officers to be visible, for the public to feel safe, be safe, and be able to position ourselves so that we can react immediately to whatever scenario we are confronted with," Atlanta Police Chief Erika Shields said. "I think that with anything you can go in with a spirit of confidence if you have prepared, and we have prepared well."

Shields said her officers will be working 12-hour shifts, reports CBS Atlanta affiliate WGCL-TV. Many agencies will fill the joint operations center starting January 26, eight days before the game, so they can all be in the same room to monitor things.

"You can never every stop learning and challenging yourself in law enforcement because unfortunately, the people who inspire the negative and want to inflict harm never stop creating," Shields said. "They never stop thinking and so you have to be there with them."

But the government shutdown is a wild card that arose relatively late in the planning process.

"Certainly there are factors that we don't control such as what's happening with our federal government shutdown and with the long TSA lines," Bottoms said. "We are continuing to encourage people to get to the airport very early."

The expected crush of travelers is significantly bigger than normal.

On a typical day, 60,000 to 80,000 passengers are screened at Atlanta's Hartsfield-Jackson Atlanta International Airport before departing, airport statistics show.

On Feb. 4, the day Bottoms calls "Mass Exodus Monday," about 110,000 passengers are expected to be departing from Atlanta's airport the day after the Super Bowl.

The partial government shutdown has meant missed paychecks for Transportation Security Administration screeners at airports nationwide.

TSA workers have been calling in sick at a rate that's been more than double what it normally is, the agency has said. That's led to a shortage of screeners at some airports across the country.

No-shows among screeners jumped Sunday and again Monday.

The TSA had a national absence rate of nearly 7 percent Monday, compared to 2.5 percent on a comparable day a year ago, the agency reported Tuesday after getting complete numbers on the absences.

A chaotic scene unfolded at Atlanta's airport on Monday, the first business day after screeners missed their first paychecks since the shutdown began. Mondays are typically busy for the airport as Atlanta business travelers depart for the work week, and some security lanes went unstaffed as lines backed up.

"Please plan ahead and give yourself 3 hours to clear security," Atlanta airport officials on Monday advised passengers via the airport's Twitter account.

Atlanta passengers led the nation Monday in terms of longest screening delays: The "maximum standard wait time" was 88 minutes, the TSA reported. Passengers who went through TSA PreCheck - an expedited screening program which is typically faster than regular lines - waited 55 minutes, statistics showed.

Friday could be the next big test for the nation's airports, as holiday travelers get away for the upcoming long holiday weekend (Martin Luther King Jr. Day is Monday). Friday is also typically a busy day for airports as business travelers head