The control tower at Newark Liberty International Airport.

The Federal Aviation Administration said late Sunday, Oct. 19 that air traffic control staffing issues were delaying travel at airports in Dallas, Chicago, Atlanta and Newark as a U.S. government shutdown became the third-longest in history.

It's not clear, however, if the issues are tied directly to the shutdown.

The FAA has had long-standing staffing issues, and air traffic controllers routinely had to work significant overtime, even before the shutdown began.

According to Cirium, an aviation data analytics company, more than 82% of flights departed on time in the U.S. in the first 17 days of the shutdown. Cirium's press release said that is average to above-average performance for the national airspace.

"I do not see any degradation in performance at the major airports below," Mike Arnot, a spokesperson for the company, said in the statement. "Any operational degradation is likely due to the recent Northeast weather; nothing that we would normally flag for reporters."

He added that flight cancellations also remain very low.

Still, the FAA said numerous staffing triggers had been received for the evening shift on Sunday, and flights could also be delayed in Las Vegas and Phoenix because of air traffic control absences.

FlightAware said more than 5,800 flights had been delayed on Sunday. Weather issues and a Formula 1 race in Austin were also impacting flights.

More than 20% of American Airlines and Southwest Airlines flights were delayed on Sunday, according to FlightAware.

Some 13,000 air traffic controllers and about 50,000 Transportation Security Administration officers must work during the government shutdown, but are not being paid.

Earlier this month, more than 23,000 flights were delayed over a week, and Transportation Secretary Sean Duffy said 53% of flight delays were due to staffing issues, compared with 5% normally, but staffing issues have largely improved over the last week.

Air traffic control has become a flashpoint in the debate over the shutdown, with both parties blaming the other. Unions and airlines have urged a quick end to the standoff.

The Trump administration is airing videos at some airport security checkpoints blaming Democrats, but many airports have refused to run them.

In 2019, during a 35-day shutdown, the number of absences by controllers and TSA officers rose as workers missed paychecks, extending checkpoint wait times at some airports. Authorities were forced to slow air traffic in New York and Washington, which put pressure on lawmakers to quickly end the standoff.

Contributing: David Shepardson, Reuters

Zach Wichter is a travel reporter and writes the Cruising Altitude column for USA TODAY. He is based in New York and you can reach him at zwichter@usatoday.com.

This article originally appeared on USA TODAY: Flight delays hit major US airports amid FAA staffing woes

Reporting by Zach Wichter, USA TODAY / USA TODAY

USA TODAY Network via Reuters Connect