House Speaker Mike Johnson on Saturday backed the Trump administration’s call for more money to rebuild the nation’s air traffic control system. He spoke one day after a nationwide ground stop kept flights on the ground for hours.

Mr. Johnson, a Louisiana Republican, made the remarks to Kayleigh McEnany on Fox News’ “Saturday in America.” Fox News said it was his first interview since the midterm elections.

He said he was in Washington this weekend working on the issue. He said Republicans were already building an “aggressive legislative package” to finish the year, and the air traffic money would be added to it.

“I give a lot of credit to President Trump and Secretary Duffy,” Mr. Johnson said. He said the two men had been warning about the problem since the start of this Congress.

On Friday night, Transportation Secretary Sean Duffy asked Congress for $50 billion to build a new system. That is up from an earlier request of about $30 billion.

Mr. Johnson said Republicans already set aside almost $13 billion for the work in the One Big Beautiful Bill, which he also called the Working Families Tax Cut. He called that money a down payment and said the bill passed with Republican votes alone.

“That investment is being made, but we need a lot more,” he said. He added that the funding should not be a fight between the two parties.

Mr. Johnson said he was sure the House committees that oversee the issue would be involved. But he said the answer was already clear: “we don’t really need any investigation to understand we need further investment.”

He said some of the equipment dates back to the 1980s and has to be updated. “We’re going to work to get it done,” he said.

At a news conference on Saturday, Mr. Duffy said the trouble began during routine work at a remote site. He said a contractor, L3Harris, was replacing old copper communication lines with fiber-optic cable when a router began flooding the system.

Mr. Duffy said officials were still working out whether the cause was a worker’s mistake or a faulty router. Officials said they did not believe it was a cyberattack.

Mr. Johnson also looked back on his three years as speaker. He called this Congress one of the most productive in the history of the House, with about a thousand bills passed.

He said it had been the honor of his life to serve as the 56th speaker of the House. He said he believes Republicans can win back the House majority in 2028.