(The Hill) – Flight delays at major airports across the country occurred on Tuesday, as staffing shortages continue amid the ongoing government shutdown.

The Federal Aviation Administration (FAA) reported shortages at airports in Nashville, Tenn., Boston, Dallas, Chicago and Philadelphia, as well as at air traffic control centers in Atlanta, Houston and the Dallas-Fort Worth area. 

In a publicly available national airspace system status summary, Reagan Washington National Airport in the nation’s capital; Philadelphia International Airport; Miami International Airport; Fort Lauderdale-Hollywood International Airport; San Francisco International Airport; LaGuardia Airport in New York City; Newark Liberty International Airport and Boston Logan International Airport could all experience ground stoppages at various points Wednesday.

The Hill has reached out to the FAA for clarity on which of the potential ground stops are due to staffing shortages.

According to flight tracking site FlightAware, over 3,600 flights within, in or out of the U.S., were delayed on Tuesday, with 70 such flights cancelled. As of Wednesday morning, 460 flights within, into or out of the country have been delayed, with 25 cancelled.

On Monday, Transportation Secretary Sean Duffy said that since the lapse in funding began last Wednesday, there has been a slight increase in air traffic controllers calling out sick. In January 2019 — during the previous shutdown, which lasted about 35 days — an increase in controllers taking sick days resulted in travel disruptions along the East Coast. 

Later in the day, the Department of Transportation (DOT) reported staffing shortages at Newark, Hollywood Burbank Airport and Denver International Airport.

According to the DOT shutdown contingency plan, over 11,000 FAA employees would be furloughed, accounting for roughly a quarter of the agency’s workforce. But the plan noted that over 13,000 air traffic controllers would keep their jobs, with hiring and training continuing. 

The Associated Press contributed.