Diesels have changed since then
For example, several companies are developing diesel engines for light airplanes. What? Aren't diesels heavy and don't they pollute too much? Not anymore. Consider the engine being developed by Teledyne Continental - a two-stroke turbocharged diesel that weighs less and uses much less fuel than the equivalent gasoline engine. It also has fewer parts, can use different types of fuel (avgas availability is a concern), runs smoother, runs quieters, and lasts longer than gasoline engines of the same power with much lower emissions. I don't know when they'll be on the market but I WANT ONE FOR MY PLANE!