Think of it this way. Paul said all the believers WILL NOT experience death. BUT ALL WILL be changed in a moment and twinkling of an eye. Paul grouped all Christians into two sets with one of those who will die and the second of those alive, and then say both these people will be changed. And then for it to say that this change will occur in a moment at a particular sound of a trumpet -- both dead and living -- it has to be at the same time. On top of that,
1 Thess 4 speaks also of the dead and living, and says both groups will rise in the air, with the dead rising first, and the living rising to be TOGETHER WITH THEM to MEET THE LORD, the Lord has to be COMING in order for them to MEET HIM. The Greek term for MEET implies His coming to us and we moving towards Him to be with Him.
The PHYSICAL part comes from
1 Cor 15 where it can only be talking about PHYSICAL BODIES being changed from natural ones to immortal ones, like Jesus was physically made immortal in his resurrection. So, apply the PHYSICAL CHANGE of the bodies of both the dead and the living, and couple that with the catching away in 1 Thess4, and it has to be a physical bodily catching away.
These things were considered for centuries and well though out and studied. I believe we will physically leave this earth. Why else would
1 Cor 15 stress a physical change of bodies for the dead if they are not going to physically rise according to
1 Thess 4? Why have a physical new body from the grave and not rise physically according to the info on rising in
1 Thess 4?