I would imagine that the gelling problems ethanol can sometimes cause in automobiles is magnified when used for aircraft due to the thermal dynamics present in aviation (the temperature drop while in-flight) that aren’t a factor for most automobiles. That’s just my intuition, I’m sure there are better informed people here who know better.
Yup, also, there are specific chemistries used in some composite wet-wing designs that can be damaged by ethanol. It's the final reason I became less interested in the DarkAero 1 while following its development.
