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Downsview Airport, located in northwest Toronto, has undergone several changes over time. About 100 years ago, the first airfield was built. A short airstrip and industrial buildings were built between farmers’ fields. It was the home of de Havilland Canada, a pioneering global airline.
It became a center for fighter aircraft production during World War II, and in the early 1990s the airfield was acquired by Canadian aerospace manufacturer Bombardier. It closed in 2024 due to company relocation.
But in early 2026, construction will begin on what will be the site’s biggest evolution yet. The 370-acre area is being developed as an urban district that will accommodate more than 50,000 residents and 75 acres of green and open space. It will be “YZD,” a nod to the airport’s former call sign, and will be developed over 30 years and at a cost of $30 billion, making it one of the largest projects of its kind in North America.
The centerpiece of the site, a two-kilometre-long airstrip, will become a pedestrian park connecting seven districts. Although each facility will be different, with its own housing, library, shops, school and community center, the runway will serve as the “connective tissue” that will tie them all together “while respecting and celebrating the site’s aerospace heritage,” said Derek Goring, CEO of Northcrest Developments, the company leading the project.
He told CNN that preserving the history of the site is an important part of Northcrest’s vision and a huge benefit. “One of the biggest challenges with large-scale urban redevelopment is that if you don’t have anything to start with, it can feel mundane,” he said. “We want to make the most of what’s there and use it as much as possible. It brings character and helps make it more interesting and unique.”
Preserving the history of this place is not just an emotional decision, but a pragmatic one in terms of environmental impact.
“There’s a lot of carbon embedded in existing buildings, and there are significant carbon benefits to preserving them rather than demolishing them and building everything new,” Goring said.
See in photos: The second life of a former airport
Vast industrial airport hangars built between the 1950s and 1990s will be maintained and repurposed as commercial buildings for film production, light industry, and clean technology. The roofs will be covered with grass and plants, which developers claim will help absorb rainwater and reduce the risk of flooding, while increasing biodiversity in the city centre.
Although the runway will not be maintained in its current form, the concrete and asphalt made from it can be reused as aggregate for roads and pavements, Goring said. Several other airports and military bases across Canada have been found to contain “permanent chemicals” that can contaminate groundwater. The developers said that while a small portion of the YZD site “reflects a historic industrial and military past”, they will continue to review the site, employing specialist environmental consultants “to help understand and mitigate heritage conditions” and working with local authorities.
Landscape architecture firm Michael Van Valkenburgh Associates (MVVA) has been tasked with creating a design concept for the runway after winning an international competition for the project in October. Its goal is to restore nature to the universe.
MVVA partner Emily Muller de Celis recalls the site’s history before it became an airfield and farmland, and when it was part of the Carolina Forest in southern Ontario. They want to recreate their original habitat and invite wildlife back into the area.
“Nature within the existing site had to be restrained to make it safe for air operations,” she explained. This meant preventing the birds from nesting, despite being located along the Atlantic Flyway, a major migratory route.
“Rewilding” the site would also have significant water management benefits, she said. The YZD site is located in Toronto’s highlands, between major watersheds. Through design, MVVA wants to find ways to absorb as much water as possible to reduce flooding risk downstream. This is done through strategic tree planting and the use of bioswales (vegetated channels that collect, filter and absorb rainwater).
Environmental sustainability is reflected in Northcrest’s overall vision. Goring said this major development would take 30 years to complete, so they needed to look to the future and prepare for further extreme weather events and the potential impacts of climate change.
He added that Northcrest is collaborating with Danish landscape designer SLA (known for work such as converting Copenhagen’s waste-to-energy plant into a ski resort), based on the “City Nature” concept of creating more green spaces in urban environments to improve quality of life.
The YZD site is already surrounded by a train station and subway network, so the design takes advantage of these to encourage pedestrianization and car-free alternatives. Wide bike lanes and a last-mile bus system will be installed.
“We’re not going to eliminate cars, the airstrip is really the only car-free area,” Goring said, “but we’re trying to make walking and cycling the easiest, safest and most convenient way to get around.”
Repurposing abandoned airfields into green parks and sustainable living areas has become something of a global trend, with examples such as Berlin’s Tempelhoferfeld and Athens’ Ellinikon Metropolitan Park.
The YZD is different, argues Goring. “The fact that our site is located in the geographic center of Canada’s largest metropolitan area and has existing public transportation infrastructure means it is more of a city-building exercise than a park,” he said.
Construction on the first district, the 100-acre “Hangar District,” will begin early next year and include 3,000 new homes, with completion scheduled for 2031. This will be the first phase of a 30-year transformation, with districts being built one by one and airstrips slowly being built between all districts.
One of the biggest challenges of this project is its huge size and the time it will take to build. Goring said they don’t have $30 billion in cash, so they intend to build it in stages: invest, take profits and reinvest.
After such a long development period, he expects the current ideas and designs to evolve. The goal is not to be overly prescriptive from the beginning. “The world is going to change a lot…[We’re]not trying to decide in 2025 what the future should look like 20 or 30 years from now,” he said.
“Ultimately, it’s about providing a really high quality of life,” he added, aiming to integrate into the current city. “We want it to feel like a part of Toronto.”
