mark wrote:

Ken you are assuming that you are going to get this mixture cheaper. In
fact it might even be more expensive than straight av gas. The difference
would be is that it would be available. The avgas you currently burn may
not be either by regulation or supply.

That's not how it's played out in places that have invested heavily in
alcohol fuels. In Brazil for example, fuel grade alcohol sells for about
1/5th the cost of gasoline.
In North America, regulation will likely prevent gouging since there
will not only be supply-side issues but also environmental issues and if
environmentally sensitive governments want people to switch to alcohol
it's likely they will move to prevent excess "profit taking"

Aviation is shrinking so fast that there will come a time when the oil
companies are no longer making enough of it to justify its continued
production. It may not be far off.

That's possible certainly but one of the reasons aviation is shrinking
is the cost of avgas. When I started flying I could fill up a C-172 for
a cool $15.00...and while I make a lot more now than I did then, fuel
costs are a significantly higher proportion of my per-hour flying costs
than they were was back then...When I'm sitting around the club, the
main bitch I hear is the cost of fuel and how it's keeping so many on
the ground...

The big difference between cars and airplanes when dealing with these types
of issues is the lifespan of the product. How many people junk a 10 year
old airplane? Lots of junk 10 year old cars. We want an airplane to last
for 50 not 10 years. Even a slight problems become major with time. An
auto is just not intended to be in service that long (though some are as the
collector car business is doing well) .

These are all just technical problems that can (and I expect) will be
solved. It remains to be seen whether the solutions will be affordable
for general aviation...

....Ken