Further to the running costs: if replacing battery cells worn out by 700 one-hour-flight cycles costs €12,000 (again citing http://www.flypipistrel.com/price-lists/PIPISTREL-ALPHA-ELEC...), that’s €17.14/hour, which is over AU$26.

So if you consider that to be a “fuel cost” (seems reasonable to me), then your “$3 an hour to run the plane's engine” has multiplied by ten—so much for “one-tenth the cost of a fuel engine”! (Yes, to make the comparison fair we need to factor engine maintenance costs into it, which can reasonably be expected to fall in the electric motor’s favour, but I don’t care to speculate how it may balance out this matter of the battery cost.)