Fleet age must impact on this figure. I assume that if you compare Qf to
VB you should only use 737NG fleets (to keep an apples/apples comparison) . The older the beast the more dollar hungry they become to maintain.
Yep. The really good thing about 73 fleets is that there is a huge amount of performance data available for them. Given the predicatability of their maintenance demand algorithms can be developed to quite accurately predict what will be required across the entire fleet (law of averages etc).