A landmark Quebec jet deal gives Carney a global win. Can it actually deliver?

On the stage at Airbus’s Mirabel facility north of Montreal, AirAsia’s charismatic chief executive, Tony Fernandes looked down at Prime Minister Mark Carney and then across the audience, and, in his British accent, made the relationship official.

“We’re officially married,” he said, reflecting on the deepening relationship between Canada and the low-cost airline he took over back in 2001. He just put in the largest single order for a Canadian-made commercial aircraft.

The 150 Airbus A220-300s ordered...