05:35 PM EDT, 05/05/2025 (MT Newswires) -- (Updates with Federal Aviation Administration's comments starting in the fifth paragraph.)

United Airlines (UAL) is cancelling 35 round-trip flights a day from Newark airport due to Federal Aviation Administration staffing and technology issues, Chief Executive Scott Kirby said Friday.

Kirby said technology issues forced the airline to divert, delay, or cancel flights in the last few days. These were compounded when over 20% of the FAA controllers for Newark, which has been "chronically understaffed," walked off the job, Kirby said.

Kirby said he spoke with US Transportation Secretary Sean Duffy on Friday and learned that the agency has drafted a proposal for "a large, systemwide investment in FAA technology, infrastructure and staffing."

Kirby urged that Newark be designated as a slot-controlled, Level 3 airport to address these issues.

The FAA said in a statement emailed to MT Newswires late Monday regarding the Newark outages and delays that an "antiquated air traffic control system is affecting [its] workforce."

"As Secretary Duffy has said, we must get the best safety technology in the hands of controllers as soon as possible," the FAA said. "We are working to ensure the current telecommunications equipment is more reliable in the New York area by establishing a more resilient and redundant configuration with the local exchange carriers."

The agency also said that "some controllers at the Philadelphia TRACON who work Newark arrivals and departures have taken time off to recover from the stress of multiple recent outages."

"While we cannot quickly replace them due to this highly specialized profession, we continue to train controllers who will eventually be assigned to this busy airspace," the FAA said.