Whatever Happened To Mogas For Airplanes, Anyway?
It's still out there, but it can be awfully hard to find. There are two reasons: one is that the price difference between mogas and avgas has narrowed substantially since the heyday of mogas for airplanes during the late 1980s and early 1990s. Then there's ethanol, which the vast majority of autogas contains these days, so-called E10, which is up to 10 percent ethanol. In addition to being hydroscopic, (it attracts water) ethanol is also incompatible with some seals, gaskets and O-rings, or so the earlier research seems to suggest.
It is possible to find mogas, however, and in a podcast, Kent Misegades tells AVweb how you can go about finding mogas for one thing, or getting a pump facility on your airport for another. It might not work everywhere, but there are a couple of grass roots coalitions and some web sites that can help.