A vote on President Biden’s choice to run the Federal Aviation Administration was delayed indefinitely Wednesday in the face of an opposition blitz by Republicans, who say the nominee lacks enough experience in aviation to lead the agency, which is under pressure to stem a surge in dangerous close calls between planes.

The Senate Commerce Committee was scheduled to vote on Denver International Airport CEO Phillip Washington, whose nomination has languished since Biden announced his choice last July.

Phillip Washington, the nominee to become administrator of the Federal Aviation Administration, testifies before the Senate Commerce, Science and Transportation Committee at the Capitol in Washington on March 1. J. Scott Applewhite/Associated Press, file

Committee Chair Maria Cantwell, D-Wash., an ardent supporter of the nominee, said the vote would be delayed to gather information requested by senators. She gave no date for a vote, “but we would like to do it soon.”

Democrats hold a 14-13 edge on the committee, so the defection of one could derail the nomination if all Republicans oppose it. The GOP has targeted Democrats and independents from swing or red-leaning states.

Most Democrats on the panel say they will support Washington, but it isn’t clear if there are enough votes to move the nomination forward. Kyrsten Sinema of Arizona, a Democrat until she switched to independent in December, and a moderate Democrat, Jon Tester of Montana, have not said how they will vote.

“I don’t know that we’re even (going to) vote on him, so I didn’t even have to take a stand,” Tester told reporters after the committee meeting.

Sinema’s office did not respond to a request for comment Wednesday. At Washington’s nomination hearing this month, she praised his service in the U.S. Army and work at transit agencies, but said he had “comparatively less experience working in aviation,” which she said was “important for this position.”

White House press secretary Karine Jean-Pierre reiterated the administration’s support for Washington, saying he “has the qualifications” for the job.

“He has led the Denver International Airport, one of the busiest airports in the world, managed a large transportation-safety organization, has served as a command sergeant major in the military. This is a role with a key safety mandate,” she said. “We are going to continue to urge the Senate to move swiftly on his confirmation.”

The FAA has not had a Senate-confirmed administrator since March 2022, when Stephen Dickson stepped down midway through his term. The agency is being led by an acting administrator, Billy Nolen.

The FAA administrator is not a cabinet-level job, but Republicans have turned the nomination into a high-profile contest with Biden and Senate Democrats.

Washington ran transit agencies in Denver and Los Angeles, but his only aviation-related experience has come since taking the top job at the Denver airport in July 2021. Washington has strong ties to the administration — he led the incoming Biden administration’s transition team for the Transportation Department, which includes the FAA.

Republicans argue, however, that he lacks experience in FAA’s core mission of aviation safety. They note that he is not a pilot.

“This is a job for someone with specialized knowledge needed to ensure the safety of the flying public,” Sen. Ted Cruz, R-Texas, said Tuesday on the Senate floor. “Phil Washington is objectively, indisputably unqualified to lead the FAA.”

Republicans have also seized on Washington’s name appearing in search warrants related to a corruption investigation in Los Angeles. At his hearing three weeks ago, Washington said he had not heard from anyone in law enforcement about the matter.

The FAA is struggling to repair its reputation since approving Boeing planes that crashed in 2018 and 2019, killing 346 people; to deal with understaffing that contributes to flight delays; and to replace an aging safety-alert system that briefly grounded flights nationwide in January. And now it is trying to reassure travelers that there won’t be more frightening incidents of planes coming too close together around runways.

The National Transportation Safety Board is examining six recent close calls between planes. In one, an incoming FedEx plane came within less than 100 feet (30 meters) of a departing Southwest jet after an air traffic controller cleared both to use the same runway in Austin, Texas.

On Wednesday, the FAA issued an alert urging pilots and others in aviation to stress the importance of following safety procedures after a “number of notable and high visibility events” this year.

“While the overall numbers do not reflect an increase in incidents and occurrences, the potential severity of these events is concerning,” the FAA said in the alert.

The FAA held a “safety summit” last week, at which Transportation Secretary Pete Buttigieg, NTSB Chair Jennifer Homendy and others said airlines, pilots and regulators need to learn from recent close calls to prevent accidents.

Zeke Miller and Stephen Groves in Washington contributed to this report.