Put a bio-diesel kit on it and you can fly almost for free.
Startup on the ramp and everyone will wonder where the Chinese
restaurant is.

A coworker has a diesel pickup with a 150 gallon tank in the bed (20
mpg, 3000 miles per fillup). He hasn't bought fuel in the past year. He
goes to oriental restaurants and dumpster dives for the used oil. He
filters it and adds it to his tank.