The assessment is right now that 65 is the correct answer when we look at our present defence commitments at the various NORAD alert levels, plus, by and large, a standing commitment to NATO. That is how the number was derived.
With some of our fleets, for example the C-130 fleet, we bought more C-130s in small packets over time, so the size and shape in the fleet we deliver at any one time doesn't necessarily have to be stagnant. The future security environment could demand an increase in those numbers.
The number today is 65. In the future, would we need more flexibility? Would we need to consider replacing attrition aircraft if we were to lose some? Those are good questions to consider and think about, but at the end of the day, defence has to be affordable, and in today's situation and the extant commitments we have, 65 is the number that we've derived.