If you were alone on the planet, what would you do?

[A. Secular Human]

I'd go to the nearest Air Force training facility and use it to learn to fly high-performance planes.  Then I'd spend the rest of my days flying F-35s or whatever supersonic jets were around.

You might want to use their training facilities and learn all the electrical, hydraulic and mechanical systems first.

The more complex the machine the higher degree of preventive maintenance it will need.

I can handle piston engines with magnetos and carbs...... I don't think I would do so well on turbines and fly by wire computers....

When you've got nothing but time, you can start with the basics.  I didn't say it would be quick.  I would probably train for a couple years from the ground up.  It would be totally worth it. 

I have sort of a head start, with an engineering degree and knowledge of the fundamentals of flight from slope-soaring RC sailplanes...

I probably wouldn't drink beer and smoke dope before climbing into the cockpit of an F-35, though.