I don’t think they’re either. Fascists fall under the bottom left quadrant of the Nolan Chart for supporting liberal economic and conservative social systems. Libertarians are placed opposite them on the top right. Left wing on the top left for liberal social and liberal economic, and right wing on the bottom right for conservative social and conservative economic.
My point is if you place them on the right of a straight line, you’re defining your line to weigh on social policy over economic policy. Therefore you must place Libertarians on the far left, despite their staunch objection to tax generated social systems. A line simply doesn’t work.