And the schedule drives everything. Until a schedule is pretty solidly finalised, at least in terms of frequencies, business planning is at best just estimation. Schedules drive capacity, which drives revenue. Schedules also drive costs. Costs and revenues are the basis of the plan, and drive cash flows, cash requirement and that in turn drives the funding plan.
If the schedule isn't bolted down, then all else is a bit woolly.
Alternatively, they are assuming that the slots will be available in the same form as their plans - which is one hell of a business risk.
TA