Now I've checked the time-tables and here is the time-comparison.
CA CPH-CAN: 14:40 with 2:20 stop in PEK
AY CPH-CAN (only summer-season): 29:15 (!) with a 18h stop in HEL.
No, I am not joking. This is the best option finnair.com offered me on a few sample searches in may. Either 29:15 or 32:30 travel time.
Finnair.com does not seem to sell any ticket wintertime anymore, neither via HKG nor PEK. If you buy a second ticket yourself then Finnair will ofcourse refuse to check baggage, but you can do CPH-CAN via HKG in 17:55:
CPH-HKG: 12:20
HKG stop 4:30
HKG-CAN 1:05
For those few cities that AY does serve, the comparision is to AY advantage, but not very much. Not sure a 12h travel time versus a 14h travel time would be decisive for most people.