well, if you're not going to fly in the winter, or the cold... why not? I'd suppose this probably increases gas mileage by weight savings. For that matter, why not wrap it in a bit of cellophane if you needed to?

https://dailytimewaster.blogspot.com/2015/10/looks-like-half-built-airplane.html

it's a Zlin Savage Bobber

Base aircraft features include an 18-gallon fuel tank, 153 square foot wing surface area, a maximum takeoff weight off 1,234 pounds, and a load capacity of 639 pounds.  Costs around 70 thou

https://www.clad.com/zlin-aviation-savage-bobber-airplane/