A sky less travelled
The lightning barriers only go so high. The lands and seas are full of terrors. So taking to the skies should be attractive. But assume people, ghosts, hulls and hollows don’t. Why?
Now it could be because they’re flightless. But I’d like to explore a different angle: what if they could fly but choose not to, or what if they could fly but something grounds them. Ideas?
The sky is a realm of demons. Brave aviators have attempted to explore the sky but have met with increasing demonic assaults and possessions. Most expeditions are lost, and those that do return come back possessed to a man. Only the most reckless or desperate crew would attempt the sky.
There is a myth of an angelic realm above the demon sky, but none have yet to break through the demon realm to reach it. If it even exists.
Or: demon blood turns inert after a certain altitude. This makes air transportation unachievable beyong certain supernatural powers. Also, hydrogen does not exist and/or has not been discovered.
Ghosts don’t fly because they cannot stray too far beyond the places that bind them to this existence.
Whatever is up there feeds on the sun.
The clouds are hungry, their bite so cold the living spirit will freeze.
Some arcanists believe that snowflakes are the frozen spirits of the dead who rose too high after the Gates of Death fell.
The dimmer sister moons might reveal a path of (relative) safety to roam above.