Is there a source to look up the percentage of flight cancellations with Air Canada? I am interested to compare this data with my own experience: On a long-distance trip with four Air Canada flights two were cancelled.
Cancellation rates are not constant over longer periods: cancellations tend to happen in groups.
- Any large scale disruption (due to storms, snow, ice, heavy rain, high winds, volcanoes, strikes…) will affect many flights in a short period, while over a period of the same duration a month before or after the rate could be a lot smaller
- Even small local disruptions (an issue with a plane, crew being ill or unavailable for any other reason, a local problem at an airport…) can affect several flights in a row and have knock-on effects for a few days (as you end up with planes and crew not in the right places at the right times).
- Busy periods can result in small problems having larger consequences, because there is less “buffer” (less spare aircraft and reserve crew available compared to the requirements).
So you could book 100 flights one month and the same 100 flights a month later and have completely different results.
In any case, 4 flights is definitely not a representative sample, especially if flights are somehow linked (the same aircraft or crew would have served two or more flights) or there is a large scale disruption around (severe weather events).
If you want to take this further, you could book a single flight, and then you would have either 0% or 100% cancellation rate. As you can see, neither is representative.
While these statistics are relatively easy to come by for US airlines (and some other countries), I couldn't find anything specific to Air Canada.
Typically, cancellation rates are somewhere between 2% and 5%. There is a very good chance that Air Canada's cancellation rate sits in this range as well. Your 50% rate is an outlier and just bad luck. Cancellations are expensive for the airlines so there is a good incentive for them to minimize cancelled flights.
It's also not clear what the goal of your question is? What would you do differently if AC average rate was 0.5% or 10% ?