Yes, I understand that, but sometimes the availability issues are related to the number of times of maintenance or the level of maintenance that is required to keep the plane available. So it may be the availability of spares. Obviously that's a constraint, but if you have an aircraft that needs 10 or 20 hours of maintenance for every hour in the air, obviously the availability is constrained.
On November 23rd, 2010. See this statement in context.