I guess it's better than snakes on a plane. However, this is disturbing not just the presence of rats itself, but rats are only attracted by food source. It really speaks about the catering services that CX uses, and rats are likely to be embedded in the catering services and then got loaded on the plane.
I am not worried about CX as in the planes itself, but now I am very worried about the Catering Services and the cleanliness of it.