It was the airport of the year 2000, they said. But not, it seems, of 2004.
Mirabel never processed even half the predicted number of visitors and now a mere 800,000 drift past the check-in desks annually. Next year even they will disappear and the pride of 1975 will become a cargo terminal.
So what went wrong? In the late 1960s the city's small Dorval airport could not cope. Montreal was a key refuelling stop. Planes could not make it from Europe to the west coast of the States without a little top-up and Dorval was the place to do it. However, the government failed to foresee that planes - and their fuel tanks - would get bigger. A heck of a lot still fly over Montreal, they just no longer land.
There were other problems, too. First, there was politics. The brave citizens of Quebec elected a separatist government a year after Mirabel opened. Many not-so-brave businesses then elected to flee the state's capital city.
Then there was transport. Dorval is only 15 minutes from the city centre, but Mirabel is 45 miles away and - surprise, surprise - the planned road and rail links were never built. Passengers who had to transfer between the airports could sit for two hours in rush-hour traffic. Their plight was ammunition to the experts who argued that a city is best served by just one big airport or "hub".
They seem to be about to get their way. Dorval airport, neglected for decades, is now getting a pound;350 million make-over. Meanwhile at Mirabel, the trolleys stand empty, waiting for all those who will never make it to Arrivals.