President Trump’s proposal this week to create a corporation to regulate air traffic control follows similar initiatives in Canada and the United Kingdom, where air space privatization brought increased costs for passengers, job cuts, and financial bailout.

The proposal to create a not-for-profit corporation to control airspace, which supporters say could speed up the implementation of newer aviation technology called NextGen, is based on previous legislation that received backing from the majority of airlines and airport worker unions.

Rep. Bill Shuster (R-PA) introduced the Aviation Innovation, Reform, and Reauthorization Act, which failed in the House last year. If it’s enacted, private air space control would look similar to railroad corporation Amtrak or mortgage broker Freddie Mac, which are partnerships between the public and private sector.

Shuster, who took more 2016 campaign money from the airline industry than anyone else in the House, has been working closely with Trump.

Delta CEO Richard Anderson opposed the push for privatization last year, calling it “unnecessary and unwise.”

“Privatizing the air traffic control system is a risky and unnecessary step,” Mike Perrone, president of the Professional Aviation Safety Specialists union, said in response to Trump’s plan.

Several Federal Aviation Administration (FAA) unions also opposed Shuster’s legislation last year, saying the program would cater to special interests: “Privatizing the system jeopardizes NextGen and introduces uncertainty into the future of modernization. At a minimum, privatization will likely result in modernization coming to a standstill during the lengthy transition period as the corporation is formed and developed,” they wrote in a letter to the House Committee on Transportation and Infrastructure last year.

User fees, which Shuster’s plan would impose on aircraft operators, may get passed on to passengers, making flying more expensive.

A 2016 study by the Government Accountability Office identified major safety risks and potential cost increases associated with privatization, particularly for airline workers and passengers. The GAO also noted a lack of plan in the event of economic downturn.

“A privatized ATC system would be ‘too big to fail,’ meaning consumers or taxpayers might have to bail out the private corporation if it couldn’t pay the $10 billion plus that it costs to operate a safe system,” said Peter DeFazio (D-OR).

“Let’s face it, you can’t go out of business as a monopoly. The board finds a way to manage through it and finds a way to make it work,” said Tim Canoll, president of Air Line Pilots Association, a union.

In their letter, the FAA unions raised concern: “In the case of an economic downturn, it is not unreasonable to question whether employees may potentially lose their jobs or that the scenario will result in a monopoly ‘too big to fail,’ inevitably leading to taxpayer bailouts. Privatized models in other countries with far smaller and less complex aviation systems went through ‘growing pains,’ which included, among other things, financial bailouts, decreases in service and staffing cuts.”

Canada and the United Kingdom both privatized their air traffic control systems with mixed results. In 2001, British taxpayers paid a $112.8 million bailout for NATS, the corporation that controls their air service. Afterward, user fees increased by 30 percent. The current CEO, Martin Rolfe, previously worked as a director at aerospace company Lockheed Martin.

After Canada transferred air traffic control to nonprofit Nav Canada in 1995, the corporation cut staff by 25 percent, mostly administrative, over the next twenty years.

Despite the job cuts, and decreases in user fees, Canadians paid more to fly. In 2014, about five million Canadians drove across the border into the U.S. to take cheaper flights.

Nav Canada has been held up as a model for U.S. privatization, though DeFazio noted that U.S. airspace is roughly four times larger than Canada’s, with three times as much air traffic.

Industry user fees, the GAO study said, may go so high that pilots would stop operating under air traffic control altogether in order to save money.

The fees may also increase costs for travelers by 20 to 29 percent, according to a study by Delta. Privatization supporters say that these costs are more fair, because they only apply to people using the service, unlike taxes, which apply to everyone. Privatization opponents point out that taxes can be scaled according to income or type of purchase, while user fees get passed on to consumers at a flat rate.

The Delta study found that after Canada and the United Kingdom privatized their air traffic control, consumers saw much more expensive tickets. “This regressive model would put a heavier burden on working and middle class passengers by charging the same user fee to all, regardless of the cost of the ticket,” they wrote.

The fees may be harmful to the economy, former Rep. Allen Boyd (D-FL) wrote: “As was the case in Canada and Europe, ATC [air traffic control] privatization will inevitably be followed by user fees which would be devastating to our general aviation industry and the reliant economies. Such fees, which would require a new, large bureaucracy to facilitate collection, have been soundly rejected by Congress every time they have been proposed.”

Another major concern around airspace privatization is that corporations would have more governing power. With decisions being made by a CEO and board, both Congress and voters would lose oversight.

Boyd wrote: “It is highly likely that any private board or entity governing our air traffic control system would be dominated by the commercial airlines and hub airports. For this reason alone, it is very important that Congress continue to have oversight so that we continue to ensure that the interests and needs of all communities are served.”

Shuster’s bill required that at least four of the 11 board members represent commercial airlines. It also required that at least two board members represent air traffic or airline workers.

Major airlines, such as American Airlines, lobbied extensively in support of the bill. “For the record, we oppose privatization and would oppose the creation of a private, for-profit entity if that were on the table, but it isn’t. The FAA, to ensure the highest degree of safety, would strictly regulate the new entity.” American Airlines CEO Doug Parker said last year.

Editor’s Note: This story has been updated to correct two errors. The original version said wage freezes went into effect after Canada privatized its system. That was incorrect; Nav Canada contacted TYT Politics to say that it ended the wage freeze when it took over. The article also attributed Canadian price increases to rising user fees; Nav Canada says user fees have decreased. TYT Politics regrets the errors. Nav Canada also told TYT Politics that it “takes no position” on the current debate over privatizing the U.S. system.