Air" in the Bible represents thought, but in a very general way – our capacity to perceive ideas and the way we tend to think, rather than our specific ideas about specific things. We see the world around us through the air, and seeing corresponds to understanding. We hear through the air, and hearing corresponds to being taught and obeying. Birds fly in the air, and they represent specific thoughts and ideas. And breathing itself – taking in air and passing oxygen to the blood – represents our understanding of true spiritual ideas.

In Genesis 1:26, when used with fowls or birds of the air refers to the air we breathe, but sky, or heavens where are stars, and together these terms refer to both the spiritual and natural man, and to their food, or goods and truths. (Arcana Coelestia 57, 58)

In Genesis 3:8, the only Old Testament reference to air is in the phrase "cool of the day" (at the time of the evening breeze) which signifies the period when the church still had some spiritual perception. (Arcana Coelestia 221)

In Revelation 9:2; 16:17, air signifies the divine truth, darkened by infernal falsities. (Apocalypse Explained 541, Apocalypse Revealed 423)

In Revelation 16:17, everyone in the spiritual world breathes air according to his faith. (Apocalypse Revealed 708, Apocalypse Explained 1012, Apocalypse Revealed 708)

541. And the sun was darkened, and the air, by the smoke of the pit, signifies that the light of truth from the Lord was made thick darkness by infernal falsities. This is evident from the signification of "the sun and the air darkened," as being the light of truth from the Lord being made thick darkness (of which presently) and from the signification of "by the smoke of the pit," as being by dense falsities from hell, thus by infernal falsities. (That "smoke" signifies dense falsities, and "the pit of the abyss" the hells where and from which are falsities, see above, n. 536-539.) "The sun and the air darkened" signifies that the light of truth from the Lord was made thick darkness, for the Lord in the angelic heaven is a sun, and Divine truth proceeding from the Lord as a sun produces all the light there, and illuminates both the sight and the understanding of angels; when therefore that sun is darkened there, the light of truth, which is from the Lord, is made thick darkness; it is darkened by falsities from hell. All denial of the Divine and of Divine things by those who are merely natural comes from falsities of evil making the light of heaven thick darkness; for such look at Divine things in thick darkness, and therefore they see them as thick darkness, and in consequence deny them. Moreover, the light of heaven when it flows in with those who are in the falsities of evil actually becomes in the spiritual world thick darkness. From this it is that the evil not only do not see or understand spiritual things, that is, the things that belong to heaven and the church, but in heart they deny them. (That the Lord appears in the angelic heaven as a sun, and that Divine truth proceeding from the Lord as a sun produces all the light of heaven, thus all the intelligence and wisdom the angels have, may be seen in the work on Heaven and Hell 116-125, and 126-140.) It is said also that the "air" was darkened, meaning the light of truth, for the air gives light from the sun. "Skies" [aetheres] have a similar signification in David:

Thy mercy O Jehovah, is in the heavens; and Thy truth is even unto the skies (Psalms 36:5; 57:10; 108:4).

"Mercy" signifies the Divine good of Divine love, and "truth" Divine truth; and as Divine truth is the light of heaven, as has just been said, it is said, "Thy truth is even unto the skies;" thus "skies" in the plural signify Divine light even to the highest heaven, where it is in the highest degree. ("Skies" have a similar signification in Psalms 77:17; Psalms 78:23, 24.)