Growth

In November 1960, the airport was renamed Montreal–Dorval International Airport/Aéroport international Dorval de Montréal. On December 15 of that year the Minister of Transport inaugurated a new $30 million terminal. The structure was built by Illsley, Templeton, Archibald, and Larose. At its height, it was the largest terminal in Canada and one of the biggest in the world. It was the gateway to Canada for all European air traffic and served more than two million passengers per year. Eight years later, Montréal–Dorval International Airport underwent a major expansion program. Despite this, the government of Prime Minister of Canada Pierre Elliott Trudeau (who represented a Montreal riding) predicted that Dorval would be completely saturated by 1985 and also projected that 20 million passengers would be passing through Montreal's airports annually. They decided to construct a new airport in Sainte-Scholastique, what became Montréal–Mirabel International Airport. As the first phase in the transition that would eventually have seen Dorval closed, all international flights (except those to and from the United States) were to be transferred to the new airport in 1975.

The opening and closing of Mirabel Airport

The Trudeau government had developed Mirabel Airport to handle an expected growth in international traffic and eventually, to replace Dorval. On November 29, 1975, Mirabel International Airport went into service. With an operations zone of 70 km2 (27 sq mi) and a buffer zone of 290 km2 (110 sq mi), it became the largest airport in the world. Many connecting flights to Canadian centres were transferred to Mirabel and 23 international airlines moved their overseas activities there. As a consequence, Montréal–Dorval was repurposed to serve domestic flights and transborder flights to the United States, to eventually shift these activities to Mirabel in the future and lead to Dorval's closure for redevelopment.

However, the extra traffic never materialized. Mirabel's traffic decreased due to the advent in the 1980s of longer-range jets that did not need to refuel in Montreal before crossing the Atlantic Ocean from the major Western North American cities. Montreal's economic decline in the late 1970s and 1980s also had a significant effect on both airports' traffic, which made Mirabel's additional capacity redundant. Although this redundancy would have been resolved if Dorval was decommissioned as originally intended, public pressure supported Dorval's continued operation due to its closer proximity to downtown Montreal at 20 km (12 mi) instead of 58 km (36 mi) for Mirabel. Another obstacle of the planned transfer from Dorval to Mirabel was Air Canada's desire to keep flights in Dorval with its proximity to AVEOS workshops.

In particular, the simultaneous operation of Mirabel (international flights) and Dorval (continental flights) made Montreal less attractive to international airlines. Passengers who used Montreal in transit had to take long bus rides for connections from domestic to international flights (exacerbated by the partially-completed road links and non-existent rail connecting Mirabel to Montreal), unnecessarily complicating their journeys, while Montrealers grew to resent Mirabel as they were forced to travel far out of town for international flights. Faced with the stark economic reality of operating two Canadian points of entry, most international airlines opted to bypass Montreal altogether in favour of Toronto which enjoyed a single major airport at Pearson handling domestic and international flights. Although Dorval resumed handling international flights in 1997, international airlines were slow to return as they were content having established Toronto Pearson as their eastern Canadian gateway.

Back to Montréal–Dorval, renaissance

With all international scheduled flights returning to Montréal–Dorval in 1997, as well as charter flights in 2004, the consolidation of flights to Montréal–Dorval resulted in an increase in passenger traffic. Besides the transfer of flights, Montréal–Dorval International Airport could resume being a true hub for passengers in-transit, and those from continental flights would no longer have to travel to Mirabel to connect to international flights and vice versa. Nonetheless, this was insufficient to woo back international airlines who had already switched their eastern Canadian gateway to Toronto Pearson a decade ago.

Starting as Dorval Airport, then Montréal–Dorval International Airport, the airport was renamed Montréal–Pierre Elliott Trudeau International Airport in Trudeau's honour on January 1, 2004, by the federal government. The renaming had been announced in September 2003 by then Minister of Transport David Collenette. This move provoked some opposition, especially Quebec sovereigntists opposed to Trudeau's staunchly federalist policies. The renaming also provoked opposition from many aviation historians and enthusiasts who recalled Trudeau's role in the effort to shutter Dorval in favour of the much larger and modern Mirabel Airport, of which he was the greatest instigator of its construction.