Mmmm, as Bose X points out, I'm not treating flying as casually as driving. However with sufficient experience, even if there is significantly more to learn with flying vs driving and more checks, more skill, more attention to detail, more planning etc, those tasks should be come automated and routine with enough practice. So that everything inc the prep work in going flying is as comfortable as getting in a car and driving.
So does that level of comfort ever happen with private pilots?