Flight Cancellation Probability: How It’s Calculated
Flight cancellation probability is calculated by combining real factors: route history, air traffic control (ATC) congestion, weather forecasts, carrier on-time performance, and active strikes. Across a sample of 10,970 real flights tracked by FlightGuard, the average cancellation probability is 0.57% — roughly 1 flight in 175 — but the figure for your specific flight can be very different. To get the estimate for your own flight right now, use the flight cancellation risk checker: enter your flight number and date and you get a risk indicator built from these factors.
One honest caveat up front, because too many sites overstate this: no tool “knows” whether your flight will be cancelled. What can be done honestly is to flag higher-risk conditions from real disruption data. No crystal ball.
The starting point: the base rate
Before looking at a single flight you need the general reference. Across the 10,970 flights with a real outcome in our dataset:
| Metric | Value |
|---|---|
| Cancellation rate | 0.57% (62 of 10,970 flights) |
| Average departure delay | 8.2 min |
| Flights delayed over 15 min | 16.6% |
In plain terms: the vast majority of flights depart and arrive. A cancellation is a rare event — but a delay is not. Almost 1 flight in 6 leaves more than a quarter of an hour late. That is why cancellation probability should always be read alongside the flight delay probability.
The 5 factors that move the probability
The 0.57% base rate is the average. Your flight’s probability rises or falls with these concrete signals.
1. Route and carrier history
This is the most informative factor. Different airlines cancel at very different rates. Here are the real numbers from our sample:
| Airline | IATA | Flights (n) | Cancelled | Avg delay | Delayed >15 min |
|---|---|---|---|---|---|
| Ryanair | FR | 3,109 | 0.35% | 7.9 min | 17.8% |
| British Airways | BA | 1,820 | 0.27% | 5.0 min | 12.6% |
| Lufthansa | LH | 1,593 | 0.94% | 8.2 min | 16.6% |
| Air France | AF | 1,240 | 0.32% | 10.8 min | 17.9% |
| KLM | KL | 911 | 0.77% | 9.0 min | 17.7% |
| easyJet | U2 | 440 | 0.45% | 10.8 min | 18.9% |
| SAS | SK | 286 | 3.15% | 4.2 min | 9.4% |
| Vueling | VY | 267 | 0.00% | 8.5 min | 10.9% |
| ITA Airways | AZ | 263 | 0.00% | 11.9 min | 29.3% |
A couple of stereotypes collapse here. Ryanair (FR), often accused of axing flights, cancelled just 0.35% in our sample — fewer than Lufthansa (0.94%) and KLM (0.77%). British Airways (BA) was the most reliable of the legacy carriers, with the lowest cancellation rate (0.27%) and the shortest average delay (5.0 min). And punctuality is not the same as reliability: ITA Airways (AZ) cancelled no flights in the sample, yet had the highest share of flights more than 15 minutes late, at 29.3%. Vueling (VY) combined 0% cancellations with the lowest delay share among the low-cost carriers (10.9%).
A note on statistical honesty: for the carriers with small samples — Vueling and ITA Airways are around 260 flights each — a 0% cancellation rate means “no cancellations in that sample”, not a guarantee.
2. Airport ATC congestion
When the airspace over a hub is saturated, air traffic control imposes flow regulations: delays that propagate and, in the worst cases, cancellations. The airports currently under the most ATC pressure are, in order, Rome Fiumicino, Lisbon, Athens, Zurich, Brussels, Milan Malpensa, Bergamo, Berlin, Warsaw and Catania. The most ATC-constrained Italian nodes are therefore Rome Fiumicino, Milan Malpensa and Catania. Departing from or connecting through these airports adds risk points, especially during peak hours.
3. Weather
Fog, thunderstorms, snow and strong winds are the most common cause of a cancellation that is no fault of the airline. FlightGuard cross-references the weather forecast at the departure and arrival airports up to 16 days out: a storm front forecast to hit around the flight’s scheduled time raises the risk sharply.
4. Strikes and geopolitical events
A ground-staff strike, an air traffic controller walkout, or instability in the overflown region changes everything within hours. This factor also determines your rights: an ATC strike is generally an “extraordinary circumstance”, whereas a strike by the airline’s own staff usually is not — which means the right to compensation is preserved.
5. Carrier punctuality and recent trend
Beyond long-run history, the last few weeks on the specific route matter: a carrier that is accumulating knock-on delays is more exposed.
How FlightGuard combines the factors
The risk engine weights these signals into a 0-100 score. The main weights: ATC delays 30%, weather 14%, carrier punctuality 10%, strikes 10%, fuel 9%, trend 9%, NOTAMs 8%, geopolitics 5%, route history 5%.
| Risk score | Band | Reading |
|---|---|---|
| 0–14 | Low | Conditions within the norm |
| 15–34 | Medium | Some factors worth watching |
| 35–100 | High | Several risk factors stacking up |
Across all evaluations the average score is 13.7/100, and roughly 13.9% of flights fall into the high-risk band. To repeat the key point: the risk score does not predict a cancellation and is not “X% accurate”. It is an indicator that lines up the real disruption factors, so you know when to keep an eye on your flight and prepare.
What to do with your probability
- Low risk: travel with peace of mind, just keep an eye on the weather in the 24 hours before departure.
- Medium or high risk: consider an alternative flight or time, set up an alert, and if a cancellation does happen, check your rights.
If your flight is cancelled with less than 14 days’ notice, Regulation (EC) No 261/2004 entitles you to compensation of EUR 250, 400 or 600 depending on distance, unless extraordinary circumstances apply. The claim deadline varies by country — 6 years in the UK, 2 years in Italy, 5 years in Spain. For a carrier-specific deep dive on the most-searched low-cost airline, see why Ryanair cancels flights.
Check the probability for your flight
Average numbers are useful as a reference, but the decision is made on your specific flight. Enter your flight number and date in the flight cancellation checker: in a few seconds you get a risk score built from the real factors described here — ATC, weather, route history, carrier punctuality and strikes.
Data from 10,970 real flights (flight_history_raw, through 26 June 2026) and from over 1.6 million risk evaluations by the FlightGuard engine. Risk scores are recalculated every night with fresh data. EU261 amounts and rules per Regulation (EC) No 261/2004.
