Montreal has been cursed by bad airport planning.

Ever since Pierre Trudeau made the fateful decision to build Mirabel Airport on expropriated farmland 55 kilometres north of downtown ahead of the 1976 Olympics, air travellers to and from Canada’s second-biggest city have experienced this country’s worst airport hell. And that’s saying a lot.

For two decades after the Olympics, the cavernous and often empty Mirabel Airport handled international flights while the much older and cramped Dorval Airport on the Island of Montreal retained domestic and cross-border ones. The arrangement irritated travellers to no end. Foreign airlines began bypassing Montreal altogether. By 1996, Lufthansa, Alitalia, Varig and TAP had all said adieu to Montreal.

That’s when the Aéroports de Montréal – the independent authority set up four years earlier by Ottawa to manage both of Montreal’s airports – decided to cut its losses and consolidate all scheduled flights at Dorval, which was renamed in honour of Mr. Trudeau in 2004. The move was widely supported by business leaders. But it was also short-sighted, leading directly to the current congestion at Trudeau airport that has Montrealers dreading air travel.

The problems predate the pandemic. But the surge in air travel this year – Trudeau airport handled 14.3 million passengers in the eight months to Aug. 31, compared with 13.9 million in the same period in 2019 – has made the situation much worse.

For several weeks this summer, massive traffic jams into and out of Trudeau airport saw countless travellers with luggage exit taxis in the middle of the highway and make their way to the main terminal on foot to avoid missing their flights. The arrivals and departures decks at Montreal-Trudeau cannot accommodate existing traffic levels – and congestion is expected to get much worse for several years when construction aimed at fixing the problem gets under way in 2024.

Not that the proposed fix will offer much relief for long.

That is because Trudeau airport is landlocked, surrounded by residential neighbourhoods, with little or no space to grow. The main terminal is more than 60 years old, and despite the addition of a new wing for international flights more than a decade ago, it is dinky compared with the airy and modern (though expensive) airport terminals in Toronto, Ottawa or Calgary. Lines to the customs hall often snake back to arrival gates during afternoon rush hours.

For its part, Porter Airlines is hedging its bets by building a new terminal at the tiny St-Hubert airport south of Montreal, at which it hopes to replicate the success of downtown Toronto’s Billy Bishop Airport as a more convenient alternative to the busy Pearson airport.

In a new book, HEC Montréal professor Jacques Roy argues that the $3-billion ADM has invested in Trudeau airport since 1997 would have been better spent on upgrading highways and building a rail link to Mirabel. “We would have an airport without space constraints, open 24 hours a day and without environmental nuisances for [residents],” Prof. Roy writes in La saga des aéroports de Mirabel et Dorval. The book projects that Trudeau airport’s existing runways will reach capacity as soon as 2043, or a full quarter-century before the 2068 date ADM estimated in 2018.

ADM spokesperson Eric Forest insisted in an e-mail response that Trudeau airport’s two runways have enough remaining capacity “for several more years.” He noted that London’s Heathrow Airport, with a similar runway configuration, handled twice as many aircraft movements as Trudeau airport did in 2019. What’s more, Mr. Forest added, the number of movements at Trudeau declined 16.6 per cent in the first eight months of this year, even though passenger traffic rose, because some airlines used larger planes.

Still, Prof. Roy argues in his book that there are limits to comparisons with Heathrow. The London airport specializes in international flights with an average of 170 passengers per flight in 2019, compared with an 85-passenger commercial flight average at Trudeau airport. Domestic and cross-border flights (on which smaller planes are used) account for more than half of all Trudeau’s traffic. And the era of ever-larger planes has ended.

Unfortunately, going back on that decision to consolidate all flights at Trudeau airport would break the bank. The main terminal at Mirabel was demolished in 2014 and building a new one would cost several times the estimated $500-million Ottawa spent to build the entire airport in the early 1970s.

What’s more, the money ADM has sunk into Trudeau airport since 1997 has already left it with gross debt of almost $2.9-billion – with more to come. In a report in May, Moody’s Investor Services projected that ADM’s “capital expenditures and debt financing will increase substantially” in late 2024 as it undertakes construction work to improve access to Trudeau airport and complete a Réseau express métropolitain (REM) light-rail transit station to link the airport to downtown by 2027.

The REM’s arrival could help ease congestion if more passengers opt for public transit over taxis or their own cars. But that remains a big “if.” Chances are most REM traffic will consist of existing transit users.

Via Rail’s proposed High Frequency Rail project might displace some air traffic in the busy Toronto-Ottawa-Montreal corridor, easing congestion at Trudeau. But that project is years away from breaking ground, if it ever does.

In short, Montreal’s airport curse will not be removed any time soon.