Hi there, I was trying to base an airship off of an Effigy Wyvern, in order to make an Airship. The DM has already let me have a size increase (+1 size, +2 str -2 dex) to get it big enough for an airship, and is letting me make the insides hollow enough to live in for a while. I was wondering what some templates which do NOT increase the cost or hit dice of it (and don't give movement modes beyond flight) might be, to give it a bit more durability? Also, it is important that it not look TOO freaky! I'd be quite happy for some help, thanks!