The wind farms themselves aren't too annoying to be honest. They used to be handy for orienting you to your surroundings but now there's so many of them that they can't really be relied upon!
The worst thing is the bloody anemometer masts that spring up to research new sites. I'm not sure it'd be possible to accidentally fly into a 3-500' tall windmill but the skinny little whip aerials that they erect all over the place are damn near invisible. Even if they're marked on the map they often don't materialise until you're right on top of them.
BV
(Turning into a grumpy old man!)