"The previous bowls have been poured out upon the earth, the sea, the rivers and fountains, the sun, the throne of the beast, and the great river Euphrates. This, the last and greatest, is poured into the air; and immediately there is heard a voice out of the temple in heaven, proclaiming, "It is done!" What, then, is symbolized by the plague poured into the air? Of what is the "air" the emblem? In the Revelation the whole of nature is used as a great complex parable or symbol. What does the atmosphere especially signify? And the answer is not difficult. If earth, sea, rivers, fountains, the sun, a throne, etc., denote manifest spiritual realities, the air obviously would symbolize an invisible spiritual realm. And here we are helped by sundry hints of scripture usage."
Much more in the text:
"Many years ago, while meditating upon this precious passage of scripture, the Spirit unfolded within my consciousness the significant truth that our catching up "into the air" can never be properly understood apart from the inspired words of the same apostle Paul wherein he states, "And you hath He quickened, who were dead in trespasses and sins: 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" (Eph. 2:1-2). There are several key words or terms that unlock the storehouse of spiritual truth contained in these verses. Consider -- PRINCE, POWER, AIR, SPIRIT, WORKETH, and IN. According to these plain statements of scripture there exists a "power of the air." This "power of the air" is identified as a "spirit," and this spirit is located "in" the children of disobedience, wherein he "works." Can we not see by this that the "prince of the power of the air" is not something or someone outside of us, but a spirit-power that operates right here WITHIN MAN. Furthermore, this spirit-power that works within man also emanates from man, exerting an influence throughout the atmosphere that surrounds the earth, giving motivation to the myriad activities and events that transpire in the world, which Paul calls "the course of this world" that men walk in under the control of this "power of the air." Thus it is called the "POWER of the AIR."