Cost will go down as the static staffing costs are spread out over more block hrs.

In pilot terms that means FTB and ACL will be flying 80 hrs per month rather than 30. Extrapolate that out over the entire work force and the labor costs per ASM go down. So do the maintenance costs, facility costs, marketing costs, etc.
It is not that the actual dollar amount goes down, it is that the costs are spread out over more seats.

As for the European operation. Those seats are paid for. We would run extra sections in to many cities, but many of those cities like LHR are slot controlled. Those slots are gone. Add to Eurocontrol is going to have some sectors at reduced rates. Finally the people we got to move, have already paid for their seats, and we are in the busy time of year, so many of these flights are already full.....