Atlanta (CNN) Unusually long security lines already have plagued Atlanta's airport -- the world's busiest -- during the federal government shutdown as unpaid screeners called in sick .

Next month's Super Bowl in Atlanta will not ease any strains at Hartsfield-Jackson International Airport, and some officials are concerned that the shutdown and one of the year's biggest sporting events could combine for not only long airport lines, but also knock-on flight delays around the country.

The February 3 Super Bowl and its peripheral celebrations will draw thousands of extra fliers to the city over a week. But it's the day after -- when most will leave -- that will particularly test screeners and air traffic controllers.

Hartsfield-Jackson normally has about 70,000 to 80,000 passengers a day -- but that will jump to about 111,000 on February 4, Atlanta Mayor Keisha Lance Bottoms says.

"We are hosting one of the biggest, most-watched events in the world in just a few weeks, and there are real concerns about will our airport be up and functioning in a way that we need it to be," Bottoms told CNN on Thursday.

"We have concerns, and it's my hope that the government shutdown will be over by the time the Super Bowl gets here."

Some travelers waited in security lines for more than two hours at Atlanta's Hartsfield-Jackson International Airport on Monday. The government shutdown has led to increased absences among TSA workers nationwide, putting a strain on airport checkpoints.

Air traffic controllers' union is worried about delays around the US

The concerns aren't limited to security lines.

One of the planning meetings meant to help airports and federally employed air traffic controllers get on the same page for the Super Bowl was canceled during the shutdown, a union official says.

That could mean controllers and airports aren't as prepared for February 4's mass exodus from Atlanta as they could be -- and that could lead to flight delays in Atlanta and the rest of the country, Dan McCabe said.

The risk of delays rises largely because more private jets than usual will be flying into and out of the area's smaller airports during Super Bowl week, according to McCabe, a representative of the National Air Traffic Controllers Association.

The airspace could see up to 1,500 extra flights a day around the time of the Super Bowl, McCabe said. Untimeliness at the smaller airports could lead to delays at Hartsfield-Jackson and elsewhere, he said.

"It's all one ... airspace, so you can only fit so many airplanes in the airspace without affecting everybody," McCabe said Thursday.

"Typically that Monday right after the Super Bowl ... that's the day where your departure procedures have to be just right," he said. "The potential to introduce a lot of delay into the system nationwide is really high" unless airports and controllers operate efficiently.

That's where the planning meetings -- involving members of the controllers' union, the Federal Aviation Administration, airport officials and others -- help, McCabe said.

Four to five such meetings were held over the past year before the shutdown happened, and controllers will work off the best plans developed then, McCabe said.

Atlanta's Mercedes-Benz Stadium, seen here last year, will host the Super Bowl on February 3.

FAA: We've been planning and training for months

An FAA representative confirmed one planning meeting has been delayed, but emphasized that the FAA, law enforcement partners and others have been planning and training for the Super Bowl for months.

"While one recent meeting was delayed, we have recalled the necessary people back from furlough in order to do everything required to ensure a safe, secure, and minimally delayed event," the FAA representative said. "Due to the large increase of general aviation and charter traffic associated with Super Bowls, delays are not uncommon for these events but we have a comprehensive plan to mitigate those delays as much as practical."

About 800,000 government employees are either working without pay or on furlough during the federal shutdown, which began December 22.

Controllers like McCabe -- who works at the Atlanta region's Air Route Traffic Control Center -- are among the 420,000 federal workers considered to be essential, meaning they're expected to continue to work without compensation.

McCabe last received a paycheck on December 31. He's worried about the shutdown's effect on efficiency, not safety.

"We're going to keep you safe," he said. "Everybody at work is still focused ... at keeping planes separated."

About those security lines

As for security lines, a recent nightmarish logjam at Hartsfield-Jackson and a spike in unplanned absences among Transportation Security Administration screeners nationwide illustrate what could happen on a high-traffic day like the day after the Super Bowl.

On Monday, some passengers at the airport waited in line for more than two hours. Airport spokeswoman Elise Durham pointed to short staffing.

"Mondays are always busy days for us at Hartsfield-Jackson, but I can tell you that we are down a few security lanes because of the shutdown," Durham said.

So I'm at @ATLairport and this may be the longest security line I have ever seen. Even growing up here, and even for a Monday morning. One passenger told me he'd been waiting over an hour and still had about 30 minutes to go. pic.twitter.com/UL7EghujQI — Omar Jimenez (@OmarJimenezCNN) January 14, 2019

The TSA won't say how many absences happen at particular airports, citing security concerns. But nationally, 6.8% of the TSA workforce had unscheduled absences on Monday, compared to 2.5% on the same day a year ago, the administration said.

Because of Monday's long lines in Atlanta, the TSA flew in 20 extra officers that night, airport General Manager John Selden told the Atlanta city council.

As a result, Tuesday's wait times were down to around 25 minutes, and Wednesday's were around 15 to 30 minutes, Durham said.

For the Super Bowl, the TSA will bring in an additional 120 officers to Hartsfield-Jackson, Selden said.

Like air traffic controllers, the 51,000 TSA agents around the country are considered essential federal employees and, if they want to maintain their employment, must work despite not getting paid during the shutdown.

In an attempt to ease the financial pain, the TSA announced Sunday that it would provide a day's pay for those who were on duty the day after the lapse in funding, and also award $500 bonuses for work during the holiday travel season.

But some workers are calling in sick, or quitting, to work other jobs that can pay them.

"Many employees are reporting that they are not able to report to work due to financial limitations," the TSA said in a statement on Wednesday.

Erin Shearer, spokeswoman for the Super Bowl LIII Host Committee in Atlanta, declined to comment about air traffic and airport security for this story.

US Sen. Johnny Isakson of Georgia expressed his concern about the shutdown's potential impact on air travel and the Super Bowl on the Senate floor in Washington.

"We've got a Super Bowl coming to Atlanta, Georgia, in about three weeks -- the biggest tourism event in the world this year," he said Tuesday. "What if the largest airport in the world, that's going to bring all the people to the largest football game in the world, goes out of business because the TSA ... strikes? Then you've just cost millions of dollars to the United States of America, my home city -- the city of Atlanta -- and others."

Various groups and air travel experts have issued statements condemning the consequences of the shutdown, but the TSA and aviation experts have said flying is still safe.

"In coordination with airport & airline partners, TSA will continue to carry out the mission to secure aviation," TSA Administrator David Pekoske said Thursday on Twitter. "Security will not be compromised."

This story has been updated to correct the date of the beginning of the government shutdown.