You can be sure someone will be offering Subaru's new diesel engine for usage in light planes too.

Hopefully these new, efficient, modern diesels will replace the ancient technology gross polluters that now propel general aviation, and lead to an end to the excuses to use heavily-leaded gasoline in them. And the elites who fly in them will be less propelled to scoff at sustainability reform. Happily no altruism is required: the range is much longer and the fuel cheaper. And you can also use renewable-source diesel, which has been demonstrated practical, so the plane is a valid long-term investment.

The Junkers company in the 1930's showed diesel engines could be viable as aviation engines, but the technology at the time made them too heavy for use on most airplanes.

However, with modern materials and better engine design, this new turbodiesel aviation engine will finally fulfill the promise of such an engine, especially in terms of vastly better fuel efficiency compared to avgas-fuelled engines.

Most light aircraft can already use unleaded regular gas. Military jets and trucks use one standard fuel. Back in the day it was called winter, or arctic diesel. Jets and diesels don't really care about the fuel as long as it's clean and relatively uncontaminated.