Ephesians
King James Version (KJV)

“Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience:”
King James Version (KJV)
2:2 According to the course of this world - The word translated course properly means a long series of times, wherein one corrupt age follows another. According to the prince of the power of the air - The effect of which power all may perceive, though all do not understand the cause of it: a power unspeakably penetrating and widely diffused; but yet, as to its baneful influences, beneath the orb of believers. The evil spirits are united under one head, the seat of whose dominion is in the air. Here he sometimes raises storms, sometimes makes visionary representations, and is continually roving to and fro. The spirit that now worketh - With mighty power; and so he did, and doth in all ages. In the sons of disobedience - In all who do not believe and obey the gospel.
Eph 2:2 In time past ye walked according to the course of this world. You lived in trespasses and sins, in accordance with the spirit of the world. The prince of the power of the air. Called elsewhere "the prince of this world" (Joh 12:31 14:30 16:11), Satan. Why he is called "prince of the power of the air" is not certain; various explanations are given. Probably his subtle influences and whisperings pervade the air, and come upon us as unconsciously as the vital fluid we breathe. The Jews held that the atmosphere was the abode of evil angels. The spirit that now worketh in the children of disobedience. This spirit, that of the world, of the power of the air, is the one which inspires those who live in disobedience.