Well, it *IS* Canada, so late Oct is right around the 6+ months of Winter weather and possible de-icing time needed.

If AC plans schedules, say, 60 days at a time it may be easier to just pad the schedules .

/not AC specific but I seem to recall on other forums that most flights (without propellers) file flight plans based on Mach .78 to Mach .82 cruise speed.