I once used a caterham al year round with polished aluminium body work. By the end of the winter the salt had put small pits into the body that could not be removed. Would this happen to the chassis of an aero?

I guess it depends on the grade of alluminium used.

I was disappointed at how badly the alloy on the caterham fared and would never have the plain body finish again as it would require washing off after every winter road use.