A jet taxis past other planes at Seattle-Tacoma International Airport in 2013. There’s a bipartisan push to privatize the Federal Aviation Administration’s air-traffic controllers. (Ted S. Warren/AP)

The Federal Aviation Administration is in the middle of a hiring binge for air-traffic controllers, but just how long the 6,000 people who get the jobs can expect to work for the federal government is unclear.

Frustrated by the FAA’s bureaucratic inertia, there is bipartisan sentiment in Congress to spin off the agency’s biggest single workforce — the almost 15,000 people who control the nation’s air traffic — into a separate corporation.

Rep. John L. Mica (R-Fla.) presented a bill to the House aviation subcommittee Tuesday that would create a private corporation to govern air travel.

“The time to stop talking is now,” said Mica, a former chairman of both the subcommittee and the parent Transportation Committee. “The time to act, and act boldly, is now.”

The daunting complexity of separating a federal agency — either privatizing or creating a government corporation for part of it — was embraced Tuesday by most of the aviation committee and by six of the seven people it summoned to testify.

The panelists who backed the massive change included Paul Rinaldi, president of the air-traffic controllers union, and Douglas Parker, chief executive for American Airlines, who spoke on behalf of a coalition of major U.S. airlines.

The concept in play would move controllers to a nonprofit private corporation or government corporation similar to the U.S. Postal Service. A downsized FAA would retain responsibility for aviation safety regulations.

Congressional frustration with the FAA is regarding its faltering progress in implementing a $40 billion program known as NextGen, which is designed to revolutionize air travel in the United States. The program, in short, is described as moving the movement of airplanes from a World War II-era radar system to a GPS system that will expedite air travel at a time when demand is expected to mushroom.

In fact, NextGen is a much more complex, integrated system that requires airlines to invest billions in new on-board equipment. As the FAA has moved fitfully in delivering its share of the equipment and shaping policies, the airlines have been reluctant to pour money into an uncertain investment.

For years, the FAA has faced sharp criticism from the Government Accountability Office and the Transportation Department’s inspector general for being behind schedule and over budget on NextGen. In September, Inspector General Calvin Scovel III said in a report that the NextGen system was “years away” from implementation.

The FAA said it has made progress and pointed to a federal shutdown of the agency two years ago and sequestration as two events that injected uncertainty into its planning. Judging from the tenor of Tuesday’s hearing, spliting the air-traffic controllers and NextGen from FAA control is a matter of when and how, rather than whether doing so is a smart move.

“We have $6 billion spent on NextGen, but the airlines have seen few benefits,” said Rep. Bill Shuster (R-Pa.), who chairs the Transportation Committee. “We will never get there on the current path.” Parker, who testified on behalf of the trade group Airlines for America, pointed to dozens of other countries that have separated the regulatory and air traffic control functions, often privatizing the controllers.

“FAA’s modernization efforts have been plagued with delays,” Parker said. “Transformation, not renovation, is required.”

Bob Poole, the veteran transportation expert from the Reason Foundation, laid out for the subcommittee the FAA’s shortcomings and the means to resolve them. Poole said that the agency suffered from funding uncertainty because it is subject to the whims of Congress, that in catering to Congress and other stakeholders the FAA has too many overseers and that it labors under a culture that hinders innovation.

“It really acts as if Congress is its main customer,” Poole said.

Poole’s recommendations: separate the air traffic control system, shift some user fees from the federal government to the new entity and make airlines and other stakeholders — including airports and passengers — the overseers of the system.

“A nonprofit corporation would be best,” he said.

Separating the two functions would be as tricky as brain surgery. The subcommittee’s ranking Democrat, Rep. Rick Larsen (Wash.), said he had 60 questions that needed resolution before a split could occur. Another Democrat, Peter A. DeFazio (Ore.), raised similar concerns.

They questioned where money to pay for safety certifications and more than $4 billion for airport improvements would come from if the current user-fee revenues that flow to FAA were diverted to a separate air-traffic controller entity.

They asked whether airlines would be willing to pay much higher landing fees — as is common in Europe — to fund the split. They questioned how small and mid-sized airports would fare. And they asked who would bear the insurance liability and existing pension benefits if the controller force was privatized.

Larsen asked Rinaldi if he would expect collective bargaining rights, pensions and benefits to continue under a privatized operation.

“Absolutely,” Rinaldi replied.

Mica called his legislation a “discussion bill” and said he would not submit it until April 15.