Pilots are speaking out against an aviation industry push toward having a sole crew member in the cockpit. At a news conference in Montreal, leaders of three of the largest pilot unions representing more than 150,000 workers say a proposal to Europe’s aviation regulator aims to boost airline profits at the cost of safety.

The European Union Aviation Safety Agency is mulling a pitch by plane makers Airbus and Dassault Aviation for some aircraft to be crewed by just one pilot for part of the flight – though not during takeoff and landing – by 2027, rather than the two-pilot operation now required throughout the trip.

Jack Netskar, president of the International Federation of Air Line Pilots’ Associations, which includes some 6,200 Canadians, says the proposal would create an “unacceptable” safety risk for passengers.

“There is no replacement for the skills and experience of at least two pilots at the controls of the flight deck at all times,” he said Thursday.

Some manufacturers frame single-person flying as a solution to labour shortages and pilot fatigue, said European Cockpit Association president Otjan de Bruijn, calling the characterization “misleading and inaccurate.”

“It’s a gamble with safety,” he told reporters.

The proposal could see only one pilot at the throttle during “less challenging phases” of a flight, so typically in cruise rather than at takeoff and landing, while the other pilot or pilots rest in the back, said Janet Northcote, spokeswoman for the European aviation agency. A pair would swap places halfway through the trip, but both pilots would be in the cockpit for the first and last 45 minutes or so.

In theory, the change could mean that longer routes which previously demanded three or four pilots on an in-flight rotation could make do with just two.

The concept – still years away from potential implementation – is being investigated more intensely by the agency, said Northcote.

So-called single-pilot operations, when just one pilot is on board from start to finish, are also undergoing “some consideration” – but only for freighters, she said.

Union leaders said they aim to counter a lobbying campaign by the sector targeting regulators around the world, as well as the International Civil Aviation Organization.

The Montreal-based United Nations agency’s governing body and air navigation commission were slated to weigh the topic further after two working papers were submitted last year, but no resolutions have been adopted, said spokesman Anthony Philbin.

Pilot unions say France-based plane producer Airbus is leading the drive toward “reduced-crew operations,” while North American airlines have been reluctant to jump on board.

“It’s a sales pitch,” said Netskar. “There’s probably going to be airlines out there that find this viable – financially viable – and not considering the flight safety risk you’re entering into.”

Airbus and Dassault did not respond immediately to a request for comment.

Boeing said in an emailed statement that it has “participated in industry discussions” but safety remains its priority, with any new technology serving to strengthen it.

“Part of the reason the aviation system is as safe as it is today is because of what pilots do,” the company said.

The prospect of fewer pilots has risen along with advances in avionics technology, as well as artificial intelligence.

“As we advance AI and machine robotics, there is a clear path to bring some of that technology into the cockpit. It is the evolution of technology in aircraft that’s driving the manufacturers to consider this,” said John Gradek, a lecturer at McGill University’s aviation management program.

Machine learning and AI have already made inroads in areas ranging from flight path programming to dynamic pricing and parts production. Airbus is researching cockpit enhancements to allow single-pilot operations. Germany-based Lufthansa is deploying AI to forecast wind patterns. American Airlines, Delta Air Lines and JetBlue are all investing in the buzzy technology, while Alaskan Airlines implemented an AI-fuelled program to forge more efficient flight paths during a six-month trial period.

Nonetheless, Air Line Pilots Association International president Jason Ambrosi said abandoning two-pilot flying at all times “recklessly dismisses” lessons that airlines have learned the hard way, calling the notion “insane.”

Bird strikes, volcanic ash encounters and, in February, an incident where two planes narrowly avoided collision at the Austin airport in Texas after “the pilot saw the danger” have all showcased the importance of keeping two pilots at the controls, he said.