I absolutely love this wallpaper from Cole & Son (link below) and I believe that somekind of airships could work well as wall decals. It’s similar with hot air balloons you already have, but airhships could maybe have a more detailed look and they would go well also for example in home office or adult bedroom. Maybe with the clouds and hot air balloons.
Airships do not have specific shape or look, so there’s also a lot of room for creativity when drawing those and making them look your own.
Link: https://www.cole-and-son.com/en/collection-fornasetti/wallpaper-114/10021/