Brett,
It is entirely possible. The same shaft that normally pulls the water pump can be fitted with a pulley to pull an aeration pump. The air is not free. It will steal a lot of power from your water pump, so you may have to go to a bit longer blades on the windmill.
If you have lots of wind during the dry times, aeration will REALLY help your fish, but will add a just bit to the evaporation rate.
Merry Christmas to all!
