Sorry for bumping an old thread,but PLEASE tell me what mod(s) did you use to make the balloon? Also, is the balloon an individual object, or a set of blocks? Cause your other picture shows a balloon with different width.
Pohany tends to make a lot of their own custom mods for their creation, they're not too keen on making and maintaining a mod pack for everything they make. Though some of the stuff that they do make does ends up in the Hylotl Stuff mod. As for the item itself, this is likely a background item which cannot be interacted when placed and can have either foreground blocks and background blocks placed in the same spot with the item. The same kind of items that appears when you make your custom space station.
Thanks! most of the blocks are plain panels from avali-triage Yes! these are what I can remember: more human furniture, hylotl stuff, red kitchen set & Elithian races mod