Over the past 3 years the number of airports offering MOGAS in the United States has been on a positive trend. Many airports are starting to offer ethanol-free Mogas because the price of 100LL has been on a steady rise. According to recent studies 80% of piston powered aircraft has the ability to run on unleaded ethanol free fuel.
MOGAS enjoys great popularity in numerous countries and territories outside the United States also. Cost of 100LL fuel can reach over 15 dollars per gallon in several places, and it can be very difficult to locate and transport the fuel to remote locations.
High octane unleaded auto and biodiesel fuels for piston engines have been safely and successfully used in Europe for many years, but adoption in the United States has been slow. Airports face significant barriers to offering fuel alternatives, which include lack of pilot education, uncertainty about liability coverage, and concerns about the supply of high octane unleaded fuels that are ethanol free.
If you would like to plan a cross-country flight AIRNAV.com offers a great tool to plot the best routes available utilizing MOGAS. As with any cross-country planning, it's always a good idea to call ahead when flying into new territories to check on the availability of fuel, regardless what it is.