While the idea of believers being "caught up in the air" is mentioned, it is metaphorically describing the Second Coming. Paul is not claiming, nor even implying that Christians will disappear before all hell breaks loose on earth. In fact, the very idea of the rapture is antithetical to the narrative of scripture.
The fatalistic belief in the end of humanity, most often because of our sins or lack of virtue, is as frightening as it is harmful. If we believe that no matter what we do, the majority of us will perish in some reign of heavenly or demonic fire, what is our motivation to plan for our collective future?