Pre-Tribbers make an important argument for their model that only Paul talks about the Rapture, and so nothing in what Jesus or John recorded can be the same thing. I've dealt with the main argument for that elsewhere.
Here I want to point out that if only one Bible author recorded something, they don't have a second confirming witness and therefore can't build doctrine on it, at all. That Paul mentioned it more then once doesn't change that he's still only one witness.
I believe The Rapture was refereed to by Jesus on (at least) three occasions recorded by all three Synoptic Gospels. In Matthew 24:27-31, Mark 13:26-27, and Luke 21:27&36.
And by John in Revelation in chapters 11-14 when you study them carefully.
I also see glimpses of it in the Old Testament, in Isaiah 26 and Joel 2.
So Paul's references to it in I Thessalonians 4 and II Thessalonians 2, and to an extent I Corinthians 15 are only a piece of the picture.
