Am I reading your graph correctly?
No, the fact that different age groups drive different numbers of miles is already taken into account. You may well argue how
well it was taken into account. I'll confess I haven't read the original source in enough detail to hold an opinion, however I think it's fairly well recognised that young men are a very high risk group and their insurance premiums reflect this.
I think that element remains larger in driving than it does in flying.
In relative or absolute terms? I would agree potentially in relative terms, but not in absolute terms.