Nope, that's not heaven!

Note that “the air” (where believers are to meet Christ) is not “heaven” in contemporary Christian theology. Classical Greek authors often used the term aēr (which Paul uses here [1 Thess 4:17]) to refer to the lower atmosphere (below the moon), characterized as dense and misty, in distinction from the aethēr (the pure upper region of the stars). While we cannot simply attribute this understanding of the air to Paul without further ado, the New Testament sometimes associates the air with the domain of Satan, who is called “the ruler of the power of the air” (Eph. 2:2), a phrase essentially synonymous with the Johannine expression “the ruler of this world” (John 12:31; 14:30). Note also the association of birds (which inhabit the air) with the evil one/Satan/the devil in different versions of the parable of the sower (Matt. 13:4, 19; Mark 4:4, 15; Luke 8:5, 12). If any of these associations is relevant to 1 Thess. 4, Paul may be intending to say that redemption occurs on the devil’s “turf,” and he is powerless to impede it.—J. Richard Middleton, A New Heaven and a New Earth, 222–23 n. 12