The obvious way for President Trump to launch his push for a big, bipartisan infrastructure package would have been for the renowned developer to don a hard hat, motorcade to the nearest decaying bridge, antiquated airport, or traffic-clogged highway, and vow to rebuild America’s crumbling arteries.

He did not do that.

Instead, the president on Monday chose to kick off what the White House is calling “infrastructure week” by championing a rather obscure proposal for bureaucratic reform: the privatization of the nation’s air-traffic control system. Republicans have been batting the idea around for years as a way to shift some 30,000 unionized traffic controllers off the government payroll and get the Federal Aviation Administration out of operating a business it is responsible for regulating. It’s a serious idea that has some buy-in from key industry players, including, most notably, the union representing air-traffic controllers.

Changing the entity that directs when planes take off and land is not, however, what voters might have expected to see as the centerpiece of a $1 trillion infrastructure plan Trump promised on the campaign trail. Nevertheless, the president pitched the proposal as transformative, spicing up air-traffic control with plenty of Trump-ian flourishes at a White House ceremony. He described the status quo in dire terms— “an ancient, broken, antiquated, horrible system that doesn’t work,” he said. (“Other than that, it’s quite good,” Trump added for laughs.) And he said the principles he was endorsing would fix just about every complaint that Americans have with flying today. “We’re proposing reduced wait times, increased route efficiency, and far fewer delays,” the president promised. “Our plan will get you where you need to go more quickly, more reliably, more affordably and, yes—for the first time in a long time—on time. We will launch this air travel revolution by modernizing the outdated system of air traffic control. It’s about time.”

All those things sound nice, but to skeptics of the proposal, converting the air-traffic control system into a not-for-profit cooperative isn’t necessary to achieve them. The key to reducing delays and increasing efficiency, they say, is not a bureaucratic overhaul but the full implementation of technology known as NextGen that is shifting air-traffic control to a satellite, GPS-based system. The shift has been slow and costly, which has led Republicans to call for getting the government out of the way. But air-traffic control, per se, isn’t the problem, and despite the outdated technology, the system’s safety record remains strong. “If something isn’t broken, why fix it?” asked Paul Hudson, a member of an FAA advisory committee and the president of a passenger advocacy group called FlyersRights.org.

Critics of privatization say it would give even more power to airlines, who largely back the idea. Funding for air-traffic control would shift from the collection of taxes on fuel and airline tickets to a user-fee model that would be established by a 13-member board. “Essentially you’re going to be privatizing the power to tax,” Hudson said.

Mark Baker, president of the Aircraft Owners and Pilots Association, said the trade group representing non-commercial aviators had heard “no complaints” about air-traffic control and would oppose new users fees. The idea also has critics on the right, who lamented that converting air-traffic control into a nonprofit was not true “privatization” and risked creating a new quasi-governmental entity like Fannie Mae or Amtrak that would require taxpayer bailouts if it failed.

Trump and his advisers argued that spinning off air-traffic control from the FAA would expedite the deployment of NextGen technology while freeing the agency to fulfill its core function as a safety regulator. “You have what is in essence a technology business embedded in a governmental agency,” said D.J. Gribbin, the president’s top infrastructure adviser.

To some extent, the momentum for privatization has grown out of frustration with Congress, which has been sticking the FAA with short-term extensions rather than long-term reauthorizations that provide the stability the industry wants. The industry has suffered from a shortage of both pilots and air traffic controllers, and the need for a stable funding stream has led the National Air Traffic Controllers Association to endorse privatization as long as the union’s contract is honored.

Where Trump and his critics agree is that his embrace of privatizing air-traffic control is emblematic of his larger, details-still-to-come infrastructure plan. For one, it’s relatively cheap. “This new entity will not need taxpayer money, which is very shocking when people hear that,” Trump boasted on Monday.

In a victory for conservatives, the president is no longer touting new public investments on a grand scale; the $1 trillion he once promised has fallen to just $200 billion in direct federal spending. Instead, he’s relying on ideas Republicans have already proposed to incentivize private development and reduce the federal role in infrastructure altogether. The president plans to promote his infrastructure plans on the road in Cincinnati on Wednesday and again back in Washington later in the week, but he is expected to focus on permitting reform rather than new federal money.

In part, that’s a political calculation. Trump has already seen the two issues Republicans most prized—health care and taxes—stall on Capitol Hill. Conservatives were never particularly excited about infrastructure to begin with, and Democrats are loathe to cooperate with Trump on anything. The president needs something—anything—to pass Congress, and if nothing else, privatizing air-traffic control was an idea that had already gotten off the ground, so to speak.

It was a priority of Representative Bill Shuster of Pennsylvania, an early Trump supporter who is chairman of the House Transportation and Infrastructure Committee, and will be key to enacting the administration’s other infrastructure proposals. Shuster said he pitched his plan to Trump back in the winter of 2014, before he even became a candidate, and the White House based its principles largely on legislation the chairman introduced last year. “It seemed like naturally low-hanging fruit from a policy perspective,”  Gribbin told reporters on Monday in explaining why the president chose to lead off with air-traffic control.

Yet in the current legislative environment, even the lowest-hanging fruit have long odds of making it into law. Shuster’s bill never made it to the House floor last year, suggesting that even Republicans were not fully onboard. The proposal ran into turf battles with the House Ways and Means Committee, which has jurisdiction over tax policy, and it is likely to draw opposition from lawmakers representing rural districts that rely more on government support.

Its path through the Senate is even rockier, since Democrats who have the power to block the measure are opposed to privatization. A lukewarm statement from Senator John Thune of South Dakota, a top Republican who leads the Commerce Committee, sent an ominous signal on Monday. “As we move forward in discussing potential reforms, getting a bill to President Trump’s desk will require bipartisan support as well as a consensus among the aviation community on a way forward,” Thune said. Another Republican, Senator Jerry Moran of Kansas, panned the proposal altogether, saying it would “threaten reliable transportation options provided by small airports and general aviation for millions of Americans.”

Trump’s best chance for a win will come in September, when Congress faces a deadline for reauthorizing the FAA and could include his proposal for overhauling air-traffic control. A more likely outcome is yet another extension. At a moment when airlines seem to be suffering one PR nightmare after another, a proposal seen as giving them more power could quickly run aground. “The last thing you’d want to do,” Hudson warned, “would be to turn the nation’s skies over to the airlines right now.”

On Monday afternoon, the president made a show of putting his signature on the statement of principles he would be sending to Congress. This wasn’t a bill-signing, of course, but with no infrastructure legislation before him and obstacles looming even for his pared-down privatization plan, it might be the closest Trump is going to get.