With Newark Airport experiencing a new round of cancellations and flight delays on Sunday, Transportation Secretary Sean Duffy said that he’s working with airline chiefs to reduce capacity at the airport while safety experts identify and correct glitches in radar and communications systems.

“The system is old. This is a system that is 25 at best, in some cases 50 years old,” Mr. Duffy told NBC’s “Meet the Press” on Sunday.  

“The equipment that we use, much of it, we can’t buy parts for now. You have to go on eBay and buy parts if one part goes down. You’re dealing with really old equipment. We’re dealing with copper wires, not fiber, not high-speed fiber. And so this is concerning.”

To modernize America’s air traffic system, the Transportation Department is working to add six new air traffic control centers and replace 600 radars, as well as upgrade its obsolete telecommunications network with new fiber, wireless, and satellite systems. An overhaul of the entire air control system will take three to four years and cost tens of billions of dollars. 

Since last month, Newark has had three losses of communications between airplanes and the control tower. The 45- to 90-second outages caused delays and cancellations to hundreds of flights.  It also resulted in several air traffic controllers taking trauma leave, adding further strain to the system, which is already 3,000 controllers shy of capacity. 

The shortage is one of the areas that Mr. Duffy said that he is addressing. Many controllers can retire at 50 years old after working for 25 years. He said he’s trying to incentivize the most experienced to stay on for several more years while newer controllers are trained. Congress also authorized Mr. Duffy to increase the mandatory retirement age for air traffic controllers to 61 from 56. 

Newark Airport has been under reconstruction for years and was expected to increase its number of available runways and double its capacity by June 15.  Earlier this week, the Federal Aviation Administration suggested that airlines operating out of Newark reduce their flights to 56 operations per hour.  The proposal calls for a voluntary reduction in and out of the airport.

Newark serves as a hub for United Airlines, whose CEO Scott Kirby told CBS’s “Face the Nation” Sunday that the slowdown is an “easy step to take” to improve on-time schedules and reduce cancellations even if the number of flights is reduced.

With reduced options should come higher prices, but Mr. Kirby said he did not see ticket prices going up at Newark, in part because of some reduction in demand among concerned travelers. He added that despite the hesitation and reduced service, demand is strong and travelers are still booking flights. 

“We’re a pretty good real time indicator of the economy at United Airlines. Everything I can see is the consumer is cautious, but still in pretty good shape,” Mr. Kirby said. “We look forward to carrying several hundred thousand customers every day this summer.”

Mr. Duffy said that the ebb and flow will be dependent on international travel, with morning and afternoon allowing for additional capacity while the arrival of international flights in the late afternoon will likely slow down operations.

“We have brought down the number of airplanes that arrive and leave,” he said. “I hate delays … but I want you to get to where you’re traveling.”

The ambitious reconstruction of America’s airline safety system comes as the federal government is looking for cost savings through the Department of Government Efficiency. Mr. Duffy said that the president and the man in charge of improving efficiency, Elon Musk, have both assured him that none of the cuts will involve air traffic controls.

“We’ve had a massive expansion of government. You can actually be more efficient and still accomplish the mission of safety,” he said.