airlines do *a LOT* of planned schedule reductions (2 to 4 months out) around the holidays to account for historically lower demand, and they have *a LOT* of historical data to use when making these scheduling decisions

as far as close-in cancellations (e.g., within 3-5 days of the flight), I’d venture to guess that many are either proactive moves to reduce network disruption due to expected weather events or in response to unplanned unavailability of flight or cabin crew members