WASHINGTON ― It was a White House decision to cut in-flight refueling on the next Air Force One, a decision that might be challenged by Congress, according to an exchange Tuesday on Capitol Hill.

The revelation came during a Senate Armed Services Committee confirmation hearing for Marine Corps Gen. Joseph F. Dunford, who was nominated to serve another term as chairman of the Joint Chiefs of Staff.

The Air Force announced in August that it would purchase two existing Boeing 747s to replace the two aging VC-25A aircraft that serve as Air Force One now. The aircraft will be modified with military communications systems and self-defense capabilities.

At the time, the Air Force said it would not require that the aircraft have in-flight refueling capabilities. The modifications are expected to be completed around 2024.

“That was a decision that was not made by the Air Force but made by the White House,” Dunford said. “I think it had to do with fiscal constraints on the program.”

In February President Donald Trump said that after discussing the program with Boeing officials for about an hour, he’d been able to find ways to cut $1 billion in costs from the $4.2 billion program.

The White House adjusted those cost savings to “millions” in April.

Dunford said the inability to do aerial refueling on Air Force One, which could serve as a national command center and protect the president if the nation were under attack, “will certainly be a limiting factor and we’ll have to plan accordingly.”

Sen. Tom Cotton, R-Ark., suggested that the design requirements may be amended by Congress.

“I think we might need to revisit that decision here on Capitol Hill,” Cotton said.