I Thessalonians 4 and Revelation 19 are definitely about different events. Problem is the term "Second Coming" isn't actually in The Bible at all. The word "Coming" in the Greek Parusia, is used in I Thessalonians 4 not Revelation 19. Revelation never uses "Coming" in reference to Jesus at all. I prefer to refer to his Second Advent which includes both events just as his first Advent had more then one "coming".
Pre-Tribbers agree those two chapters of The Bible are separate events, and make their argument against Post-Trib dependent on that to an extent. Problem is, here is how one Pre-Trib website defines them.
The Bible must see the Rapture (Jn. 14:1-4; I Cor. 15:51-58; 1 Thes. 4:13-18) and the Second Coming (Zech. 14:1-21; Matt. 24:29-31; Mk. 13:24-27; Lk. 21:25-27; Rev. 19) as separate events, because when the verses are compared they describe two very different scenarios:The excerpts from the Olivte Discourse they listed by any standard resemble I Thessalonians 4 way more then Revelation 19. And of course the Rapture has to be not in Revelation at all for them.
Here is some of how they break it down.
Rapture — believers meet Christ in the airThe Mount of Olives is only identified as relevant in Zechariah, but we know form Isaiah 63 that Jesus is in Edom first when he comes on a White Horse. Zechariah is consistent with this. Jesus is in fact back already in the prior Chapters (12-14 are all one prophecy), Israel has already "Looked upon me whom they pierced". The Mount of Olives is merely where he starts his second Triumphal Entry into Jerusalem.
Second Coming — Christ returns to the Mount of Olives to meet the believers on earth
Christians want to see the Mount of Olives as relevant to his return because it gives symmetry to the Ascension where he left from there. But I'm afraid there is no solid Biblical basis for it.
Rapture — living believers obtain glorified bodiesGood so far I guess. Nothing said about the Revelation 19 event precludes change however.
Second Coming — living believers remain in same bodies
Rapture — believers go to heavenThis is where the problem really begins. Because Matthew 24 and Mark 13 clearly describes Jesus taking his people from the Earth to Heaven.
Second Coming — glorified believers come from heaven, earthly believers stay on earth
Rapture — no signs precede itThis is the reason they need Matthew 24 to not be about The Rapture. At any rate Paul in II Thessalonians 2 refers back to what he talked about in 1 Thessalonians 4 and clarifies that signs will proceed it.
Second Coming — many signs precede it
Rapture — revealed only in New TestamentI believe there are at least two maybe three Rapture passages in the Old Testament, and even Pre-Tirbbers are beginning to accept this.
Second Coming — revealed in both Old and New Testaments
Matthew 24 uses the word Parusia which Paul also does in II Thessalonians 4. Revelation doesn't use it at all.
Matthew 24 and II Thessalonians 4 refer to Jesus coming in the Clouds, in Revelation 19 and Isaiah 63 he comes on a White Horse. But the Son of Man is on a Cloud in Revelation 14.
Matthew 24 and II Thessalonians 4 and 1 Corinthians 15 refers to a Trumpet, Revelation 19 does not, Revelation's Last Trumpet was the 7th in Chapter 11, which alludes to the Bema Judgment and the Resurrection of the Dead.
The word Harpazto from which via Latin we get Rapture from II Thessalonians 4 is use din Revelation in Chapter 12.