I'm curious how the rule counts cancellations in order for an airline to achieve the 10% reduction number. Obviously airlines are more likely to cancel RJ flights or flights between a hub and a small spoke outstation. However, such flights generally only touch one airport on the list of 40, while by definition hub-to-hub or more generally 40airport-to-40airport flights hit one of the 40 in both directions, so that would use twice as much scarce ATC resources.

Similarly one could argue that a go around consumes more ATC resources that a landing. Needed go arounds won't be avoided, but an airline might proactively cancel flights that are more likely to experience a go around due to very strong winds, etc.