The Senate on Wednesday confirmed Bryan Bedford as the next administrator of the Federal Aviation Administration, handing a longtime airline executive the reins of a beleaguered agency at a critical moment for air travel safety.

Mr. Bedford, who was confirmed largely along party lines, has pledged to spearhead a crucial modernization effort as the F.A.A. works to address staffing challenges and to upgrade outdated air traffic control systems that have contributed to a series of outages, near-misses, and deadly accidents in recent months.

Last week, Congress approved $12.5 billion for the agency, funding that was praised by Transportation Secretary Sean Duffy as a “down payment” toward improvements.

But Mr. Bedford rankled Democrats last month when he would not commit to holding all commercial pilots to a federal requirement to complete 1,500 hours of training, a standard he had criticized as the chief of Republic Airways, a regional airline.

The 53 to 43 vote, in which Senator Jeanne Shaheen of New Hampshire was the only Democrat to support Mr. Bedford, reflected how his skepticism about certain safety regulations splintered support for his nomination along partisan lines.

“He has failed to show he’ll put the safety of airline passengers above protecting airlines’ profits,” Senator Chuck Schumer, Democrat of New York and the minority leader, said on the chamber floor Wednesday morning. “He is the wrong choice for anyone worried about aviation safety, particularly at a time like this.”

Mr. Bedford, who becomes the fifth person to lead the F.A.A. in the last four years, spent decades running and revitalizing airlines. He ran Republic Airways for more than two decades and has held other leadership roles in the industry, including as the chairman of the Regional Airline Association. The R.R.A. was one of several airlines and trade associations that endorsed Mr. Bedford’s bid, as did the air traffic controllers’ union.

As an airline executive, Mr. Bedford challenged some of the F.A.A.’s regulations. In 2014, he argued in congressional testimony that the agency’s 1,500-hour pilot training rule — which Congress ordered following a deadly Colgan Air crash near Buffalo, N.Y., in 2009 — was “arbitrary.”

In 2022, Republic Airways petitioned the F.A.A. to allow graduates of its flight school, the LIFT Academy, to be certified to pilot commercial aircraft after only 750 hours of training, the same number of training hours that military pilots are required to complete in order to be certified to pilot commercial flights. The petition was denied.

During his confirmation hearing before the Senate Committee on Commerce, Science and Transportation last month, Mr. Bedford refused to rule out doling out similar waivers if confirmed as F.A.A. administrator, declining even to pledge to hold off until the agency had addressed understaffing at air traffic control towers.

“I’m a big supporter of structured training as opposed to pure time-building,” he told senators during his testimony. He added, “I don’t believe safety is static.”