I took my Mavid Pro on carnival Sunshine on my last cruise in 2018. Had no problems, kept it in my cabin and use it ashore. BUT. On my Upcoming cruise Oct 1st this year on carnival Marti Gras, I was reading the list.. And they require you to give the drone to security when you board the ship, and "check it out" when in ports. In that case, I decided to not take my drone on this trip.
So at the time of this posting, Carnival will allow Drones, but you have to leave them with security while your on the ship.