global reserve is reserve on fleets in bases which have global flying, essentially Europe and Asia (Deep South America may be in there to, I can’t remember). This changes the reserve rules slightly. You get 6 “holy days off” which they can’t roll trips into. These 6 days have to be consecutive. The rest of your days off can have a trip rolled into given certain parameters.

fleets that don’t have global flying have only one flexible day off per month, a trip can be rolled into that given certain parameters. You always get those days off back later in the month.