July 18, 2025
Ever wonder why your flight was delayed or grounded? Maybe you heard it was due to weather, or “traffic volume”, or something vague like “constraints”. What you likely didn’t hear is that behind that decision were dozens of experts across Canada working together to keep air traffic flowing safely.
At the heart of that effort is NAV CANADA’s National Operations Centre (NOC). Based in Ottawa, this team takes a nationwide view of Canada’s airspace and coordinates responses to everything from weather disruptions to runway closures—working closely with airlines, airports and air traffic service professionals to keep the system running smoothly.
To better understand how these decisions are made, we spoke with Derek Allen, National Operations Manager at the NOC, for a behind-the-scenes look at the people, planning and real-time collaboration that keeps air traffic moving.
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Created after 9/11 as a central crisis communications hub, the National Operations Centre is now the nerve centre of Canada’s air traffic system. While local air traffic control and flight service sites are charged with the delivery of critical services within their own regions, the NOC takes a nationwide view, looking across all seven of NAV CANADA’s flight information regions (FIRs) to understand how one disruption can ripple through the entire system.
“We’re constantly monitoring from coast to coast to coast,” says Derek. “If weather moves from Toronto into Montreal, or if airspace is impacted in one place, it can set off a chain reaction that impacts flights across the country. Our job is to coordinate proactively with all the right people to keep things moving safely and efficiently.”
The NOC gathers and shares information with:
It’s a central hub for planning, responding, and communicating.
When a certain airport or region is expected to get busy because of weather, traffic volume or other constraints, the NOC may propose something called a Traffic Management Initiative, or TMI. These proposals are typically brought forward by the National Traffic Management Unit (NTMU) after internal coordination to assess available options for balancing demand. The TMI is then discussed with airline and airport partners to determine the most effective and least disruptive approach.
This could mean slowing down a few departures or arrivals, adjusting flight routes around storms, or managing how many flights can arrive per hour (Airport Arrival Rate/AAR). These initiatives help ensure the system continues to run safely and efficiently, reducing the risk of congestion and keeping delays to a minimum.
These measures aren’t made in isolation. The NOC works in close coordination with airlines, airports, and other partners to determine the most effective and least disruptive approach.
If ground delays for flow management are expected to last more than a couple of hours, the NTMU might implement a Ground Delay Program (GDP). This is a tool that manages demand by holding flights at their departure airports, spacing them out so that only a manageable number arrive at the destination over time.
Flights are assigned specific departure slots, helping to prevent overcrowding at busy arrival airports and keeping overall traffic flowing more predictably.
Contrary to popular belief, most delays that are initiated by air navigation service providers aren’t about one issue. Sometimes, NAV CANADA implements traffic management initiatives as a proactive measure. They’re usually the result of multiple, interconnected factors. These include:
“It’s like an ecosystem,” explains Derek. “Every part must work for the whole system to run smoothly. One small constraint can ripple across the entire network.”
For example, when poor weather shuts down an approach path, the NOC and NTMU work with air traffic service professionals to reassign routes, often in real time. If a storm rolls over a “bedpost”—the navigational entry point into the airspace near an airport—it can cause a chain reaction of airspace delays, even if the airport itself remains open.
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NAV CANADA holds multiple daily planning calls 365 days a year, with participants including airport operators, airline dispatchers, weather services, and air traffic service professionals. These calls provide an overview of operations for the day, which includes:
Even once a TMI or GDP is in place, the plan is not set in stone. Airlines can still request individual exceptions for flights affected by crew availability, maintenance, or operational constraints. The goal is always to strike the right balance between flexibility and safety.
“What people often don’t see is the transparent and collaborative work happening behind the scenes,” says Heather McGonigal, Assistant Vice President Stakeholder & Industry Relations at NAV CANADA. “Whether it’s a routine day or one with unexpected disruptions, we’re constantly working with airports, airlines, and other aviation partners to keep operations running smoothly. We rely on their expertise to help make the best decisions for the broader ecosystem. It’s that ongoing coordination, openness, and trust that keep things moving safely and efficiently.”
Another lesser-known aspect of delay management relates to the airspace around an airport, not just the airport itself.
Imagine every airport has four “on-ramps”—called arrival fixes or bedposts—where incoming flights merge into final approach. If a storm blocks one of those paths, traffic must be rerouted over the remaining ones. Too much volume in those airspace corridors can cause delays even if the airport’s runways and gates are clear.
Most passengers only see the end result: their flight is delayed. What they don’t see is the network of hundreds of people, planning and adjusting in real time to keep things moving.
“From ground crews and airline dispatch to air traffic service professionals to our team at the NOC and the National Traffic Management Unit (NTMU)—everyone is working toward the same goal: to get people where they need to go, safely and efficiently,” Derek explains. “Safety is always the number one priority. We won’t compromise that.”
Behind even a 15-minute delay, there may have been dozens of conversations, forecast updates, reroutes, and contingency planning efforts—some involving NAV CANADA, others driven by airlines, airports, or weather services.
Canada’s air traffic system is one of the most complex and interconnected in the world—spanning vast geography, diverse weather conditions, and high volumes of traffic. And it’s managed by cross-functional teams of professionals working together in real time, every single day.
At the centre of it all, the National Operations Centre plays a key role in planning, problem-solving, and ensuring the systems runs as safely and efficiently as possible. It’s not just about managing air traffic—it’s about collaboration, coordination, and a deep commitment to getting people where they need to go.
Learn more about air traffic management initiatives and how the weather, construction, and other factors impact aviation.