This is a fun procedural effect, but currently uses a lot of GPU resources, so it might be more for tech demos than actual game development. Perhaps someone else can take the shader code and optimize it for game dev?
Based on this glsl shader code and blog post.
Effect creating using the excellent c3IDE which now has good effect support also.
Addon comes with an example project, play with the parameter values, sprite noise image and see what kind of interesting cloud flyovers you can create.
Flying over the clouds of Mars: