Av gas ain't a good idea for automotive engines. It contains chemicals to deal with altitude that automotive engines do not need. It can cause engine damage.
I never knew this. I remember as a kid, which for me was back in the early 80's, the teens would go out to the airport and fill there cars up with AV fuel. It was the only place around to get high octane. Of course I have no idea if those cars are even around any longer.