My friend made drone business startup. This is not exactly what you ask, but he begin on air photo and geodesy and spent huge amount of money and effort on it,

My friend made drone business startup. This is not exactly what you ask, but he begin on air photo and geodesy and spent huge amount of money and effort on it, with really big troubles (for example once his driver left machine to go to wc, and thieves stole equipment, which costs near quarter of Million dollars). Once he found niche of agriculture drones, and in a few months sell large truck of those drones, and now as I know, most of his business is for them. He still sell industrial drones and provide services connected to them, like computer farm, which reconstruct 3d model of terrain from drone video. But he talk about this less and less.