The one bright spot I see is that you wouldn't actually need to fly around; something akin to flying windmill designs might suffice. I think there are at least

The one bright spot I see is that you wouldn't actually need to fly around; something akin to flying windmill designs might suffice. I think there are at least three major problems here, though, each bad enough to sink the idea. First: the last major Yellowstone eruption involved 240 cubic miles of debris. Even if that's only 1% ash, that's a basically prohibitive amount of volume to remove from the upper atmosphere. Second: ash distribution is rapid and extensive. There's not enough ash in any one place to make cleanup runs effective overall, and distribution is too fast to clean a region persistently. Third: volcanic ash is some of the nastiest, most machinery-hostile stuff nature produces. I would expect it to jam and corrode basically any moving πarts we can build, while also blocking out enough light to prohibit any kind of sustained solar flight. Frankly, I don't think there is a good answer at the moment; the sheer volume of the stuff is beyond any sort of geoengineering we've seriously considered.