Oh dear, Falling leaf, WRONG!
The CSIRO ran tests on a noxious weed that had taken over the country west of Townsville and Cairns in the cattle country, back in the seventies or early eighties.
I think it was a Madagascan creeper which went mad here.
The milk from it is high in oil.
The CSIRO distilled petrol from it and found that it didn't have the nasties that eat our buildings after they are producesd in exhausts.
Like the sugar mills the waste could be used to power some of the production. They drew a square on the map of the area that could supply Oz with it's petroleum needs. It wasn't quite the 150 miles from TL to CS.
The oil companies banged THAT on the head like they have done to efficient engines.
When we FINALLY get short of ground oil we'll grow it, in the meantime the oil companies are out to get all the profits they can and squeal 'shortage' so we'll continue to buy.
Some people are sick of the oil companies and make their own diesel from old vegetable oil now. That's refined stuff not the full ingredients of plant oil. You can probably get grease from the milk (sap).
Others posting here...Look at the military all you like. THEY have parachutes!
The three dimension of air will need man flying aeroplanes for a bloody long time to come yet.