When I first started planning my cruise, I was curious too about which Royal Caribbean ship was the biggest. During a hectic week of juggling flight changes (I had to switch airports last minute). While the agent was helping me, I ended up scrolling through cruise info and learned that the biggest ship right now is Icon of the Seas.
I actually saw it in person later, and it’s massive—like a floating resort stacked on top of another resort. The funny part is, dealing with that flight change made me double-check every detail of the trip afterward. But everything worked out, and now I always tell people that number is the quickest way to handle any flight changes when planning a cruise.