I am making an airplane cake for my nephew's 1st birthday in 2 weeks and was wondering what kind of icing would be best for doing puffy clouds. Could someone please point in the right direction? Thanks your your time and help.

not sure here is a bump.

I did clouds on my cake a couple weeks ago. I just used white butter cream and piped groups of large dots to give the look of puffy clouds. I thought it turned out okay, but it was my first try. You can see it in my pictures. Hope this helps some, but I would love to hear other responses.