In applications, surface coatings need to be able to be applied to large surface areas. Superhydrophobic coatings also need to stay stable in the Cassie state. Therefore, they are often nanostructured and irregular. We investigated wetting and slippage on such a coating using fluorescence correlation spectroscopy showing that these surfaces are wetted heterogeneously. Large air inclusions may occur that possess a significantly large slip length. The work has been published in Physical Review Fluids.