Best icing for cake decorating?

[FaintlyMacabre]

It's been about 15 years since I decorated a cake but I'm going to attempt a rocket cake for my DS's 2nd birthday.
I hate fondant icing and I'm not too keen on buttercream either (yes I know the cake is for DS but I plan on eating a sizable amount slice), so are there any alternatives?

BTW I'm only planning a 2D rocket, not some 3D extravaganza like this.

those cakes!

I'm not going to be any help, but to make a nice smooth rocket, you are going to have to bite the bullet and get fondant (you can just peel it off before eating).