Talking about sustainable growth:
If we go back to simple days....
Farmers farmed the land for food....the next man doesnt but he takes wool off sheep to make clothing...They both swap a little of their stock...
that's what the world is now...except that there are more things out there and thus we now use money instead of straight swaps...
So if reply to the last message about worries of there not being enough resources for the people living...surely there's enough in terms of the simple things in life...
And in reference to aviation maybe we have to find a new energy for planes to feed off...