Yup. Optimisation is always a trade-off problem that needs to be approached intelligently, not mindlessly. The raw metric of minutes to airborne leads naturally to the intelligent points you raise about what each minute is worth.
The arbitrary target implies a cost function that is infinite below 30 minutes, and zero above it – this, if anything, suppresses intelligent discussion and leads to wasted effort.
The arbitrary target implies a cost function that is infinite below 30 minutes, and zero above it – this, if anything, suppresses intelligent discussion and leads to wasted effort.