London Heathrow – Montreal: how often flights are 3+ hours late or cancelled
Of 1,739 scheduled flights between London Heathrow and Montreal in 2025, 3.5% (95% range 2.8%–4.5%) were cancelled (44) or at least 3 hours late (about 18) — roughly 1 in 28. That is worse than 92% of 834 busy UK routes (median 1.1%). The route is 5,215 km, so when the airline is at fault UK261 compensation is £520 per passenger. This is an upper estimate: weather and air traffic control problems give no right to compensation. Source: UK CAA.
The route in 2025
| Scheduled flights (both directions) | 1,739 |
|---|---|
| Cancelled | 44 |
| Operated but 3 hours or more late | about 18 |
| On time or within 15 minutes | 76% of operated flights |
| Average delay of operated flights | 15 minutes |
| Distance | 5,215 km (great circle, LHR–YUL) |
By direction
| Direction | Scheduled flights | 3h+ late or cancelled | 95% range |
|---|---|---|---|
| From London Heathrow | 868 | 2.6% | 1.8%–3.9% |
| To London Heathrow | 871 | 4.4% | 3.3%–6.0% |
By airline
| Airline | Scheduled flights | 3h+ late or cancelled | 95% range | Cancelled |
|---|---|---|---|---|
| Air Canada | 1,034 | 4.2% | 3.2%–5.6% | 35 |
| British Airways | 705 | 2.5% | 1.6%–4.0% | 9 |
The 95% ranges overlap, so on this route no airline is clearly better or worse than another. Airlines with at least 100 scheduled flights on the route; operating companies are shown as the CAA lists them (for example easyJet UK and easyJet Europe), because that decides whether UK261 or EU261 applies.
What you may be owed
| Distance | Delay at arrival | UK261 compensation |
|---|---|---|
| 5,215 km | 3 hours or more, or a cancellation less than 14 days ahead | £520 per passenger |
Weather is a frequent reason why no compensation is due: at London Heathrow EUROCONTROL restricted arrivals for weather on 32% of days in 2018–2026.
Caveats
- This is an upper estimate of flights where compensation may be due. Weather, air traffic control, strikes by third parties and security problems are “extraordinary circumstances” and give no right to compensation; cancellations announced 14 days or more ahead do not either.
- The CAA measures delay at the UK airport (departure or arrival). The legal test is the delay on arrival at the final destination.
- Flights in both directions are combined. For flights from an EU airport, EU261 applies when the airline is an EU airline (€250 / €400 / €600), UK261 when it is a UK airline.
CAA destination name: Montreal (Dorval).