The primary circuit that failed is due to be replaced as part of a massive overhaul of the nation's air traffic control system.

The primary circuit that failed is due to be replaced as part of a massive overhaul of the nation's air traffic control system.

The primary circuit that failed is due to be replaced as part of a massive overhaul of the nation's air traffic control system.

The primary circuit that failed is due to be replaced as part of a massive overhaul of the nation's air traffic control system.

The primary circuit that failed is due to be replaced as part of a massive overhaul of the nation's air traffic control system.

PHILADELPHIA (WPVI) -- Operations at Philadelphia International Airport were returning to normal Tuesday morning, but travelers continued to experience delays and cancellations following a major equipment failure at the air traffic control facility that guides flights in and out of Philadelphia and Newark.

More than 1,000 flights were canceled nationwide and over 6,000 were delayed on Monday, with Newark and Philadelphia hit the hardest.

As of 9 a.m., there were 34 delays and 30 cancellations for flights arriving at and departing from Philadelphia International Airport.

Some passengers said they had been attempting to travel since the previous day.

"We got loaded onto the plane, and we spent three hours driving around the airport, and then we were number two in line for takeoff and they brought us back to the terminal," said Heather Albert of San Antonio, Texas.

Action News spoke to Heather and her husband Michael around 5:15 a.m. Tuesday. Their original flight was scheduled to depart around 10:45 a.m. on Monday.

Ayaan Bakshi, from Florida, said repeated delays prompted a change in plans.

"Yesterday we got to the airport at like 11 a.m., and they kept delaying my flight, and it ended up saying 8:24 p.m., so I just decided to go home, reschedule, and take the 7 a.m. flight today," Bakshi said.

The disruptions were tied to an equipment failure at Philadelphia TRACON, the air traffic control facility responsible for guiding flights in and out of Philadelphia and Newark. According to officials, a circuit failed Monday morning, cutting off the primary communications line. The backup fiber-optic line was also severed when it was accidentally cut by a New Jersey Transit construction crew working in Middlesex County.

The outage led to ground stops in Philadelphia and Newark before disruptions spread to Boston, New York City and Washington, D.C. Thousands of flights were delayed or canceled.

Action News spoke with Philadelphia Eagles fans returning from Nashville after Sunday's victory over the Tennessee Titans.

"We waited and waited and waited and finally got on a plane," Rita Moora, of Ventnor, said.

"There was a 20-minute delay, which turned into about a 12-hour delay," said Sean McGeever, of Roxborough.

The ground stop was lifted around 5 p.m. Monday, but officials warned travelers to expect continued delays and cancellations as airlines worked through the backlog.

Passengers expressed frustration with the disruptions and efforts to obtain information.

"It was horrible. They notify you but the service to try to get answers - when they said call, get a refund, do all this other stuff - completely terrible," said Pasquale, of Toms River.

Sarah Gyuris said her plans also changed because of repeated delays. She's headed to Jacksonville, Florida.

"Couldn't get out; they just kept delaying it and delaying it. So now I have to go into Orlando, which is two hours then but you know what, Go Birds," Gyuris said.

Transportation Secretary Sean Duffy said, "This incident underscores the need for additional funding to modernize aging infrastructure."

Also Monday, the FAA began testing a new computer system that uses AI to help predict schedule conflicts and weather issues to help air traffic controllers reroute traffic. But that system is initially being tested only in the Washington, D.C., area, so it did not appear to be linked to the outages.