I agree a fuel tax is pretty simple, however, do you know how high that tax would have to be to support the entire aviation infrastructure? [...] I don't know where to get an accurate assessment of the real cost of our aviation system

Costs are only half the story. Benefits are the other half. There are
invisible benefits to the system (any system) which also need to be
figured in.

Jose
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Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.