Tell us about yourself!
In Australia it would be legal as long as you follow CASA's rules on drone flights. i.. nowhere near flightpaths or within 30m of people or higher than 120m except in rural areas where you can go as high as you like.
I've thought of this before and put it on my list of things to do. Basically what you mean is to power the compressor with mechanical output of a wind turbine . I'm certain it can be done but it might be a bit of mucking around as you'd have to gear up the output to match the current electric motor speed to obtain similar performance. Has anyone else had a go at this?