From an African perspective, looking at the spirit world (Ancestors, Orishas, Alusi, Netjeru, etc.) as a whole, they are air. There's a marriage/connection between the Earth spirits and the Sky spirits. Earth (represents human life) and Sky (represents the Supreme God) is balanced and supported by the spirits/powers/energies.
Spirits/Air are the sustainers of life.
In Kemetism, Shu (Kemetic Netjer) represents air, light, wind, breath, sunlight and the atmosphere.
"In the tradition of ancient Egypt, the deity Shu represented air, breath, and the atmosphere. As the god of air and sunlight, Shu’s name means “the one who rises up,” which is related to the idea that breath and air rise." - Ana Monteiro-Ferreira
"...Shu, as air, was responsible for lifting Nut above Geb, that is, separating the sky from the Earth. In this function, Shu assumes a crucial responsibility in maintaining balance. Should Shu disappear then the sky would collapse onto the Earth and humans would be unable to survive. Should Shu lift the sky too far away from the Earth, then humans would also die because of the lack of protection from Nut. Thus, the role of air was one of sustaining life, maintaining balance, and protecting humans." - Molefi Kete Asante
Looking at the spirit world (the Ancestors, Orishas, Alusi, Netjeru, etc.) as a whole, they are air. As stated at the end of the post on Earth, there is a marriage/connection between the Earth spirits and the Sky spirits. Earth, which represents human life and sky which represents the Supreme God is balanced and supported by the spirits/powers/energies. That makes sense, seeing that we contact our Ancestors and Spirits because of the belief that God is out of reach. So the spirits/air are the sustainers of life. Air is also connected with communication and protection.
"In other African societies, Yoruba, Akan, Zulu, Kikuyu, Bakuba, and so forth, the air is a sustainer of life and also the container of numerous powers and energies." - Molefi Kete Asante