I posted an image recently of some clouds I’m working on for this fly-by idea I’m realizing. Shortly after I posted the image a friend asked me how you would go about creating large billowing clouds (the kind you see from and airplane). A quick answer would be “just create a large fluid container and adjust the Perlin texture”. That solution only leads you to extremely long and painful render times, trust me……please. The key is to keep the fluid contain as small as possible (in the Y direction) probably in the 2 to 5 scale and scale up the noise texture. Also, when scaling up the texture you’re going to need to play around with the frequency ratio to gain some of the “lumps” back into your clouds.
This is the previous image with scale adjustments as well as other adjustments to make it less dense.