Indeed. It’s a hard resource to exploit, that one, but it has been done. ;)
It’s harder to hitch a ride on a bird than it is to turn plants into car fuel, though, but, on a less silly note, the fact that so much fertilizer comes from petrochemicals and other non-renewable sources seriously limits the long-term potential of biofuels.
Well, one way to exploit the properties of air to fly is fairly common, if rather inefficient ;-)
Indeed. It’s a hard resource to exploit, that one, but it has been done. ;)
It’s harder to hitch a ride on a bird than it is to turn plants into car fuel, though, but, on a less silly note, the fact that so much fertilizer comes from petrochemicals and other non-renewable sources seriously limits the long-term potential of biofuels.