Clothed, Naked, Further Clothed

What does Scripture mean when it refers to believers who have died as those who have fallen asleep?

When believers die, they depart from their bodies and immediately come into the presence of the Lord.

At the Lord's return, those who have died will collect their "sleeping" bodies from the earth and sea, be clothed with immortality, and meet the Lord in the air.

Immediately following this, we who are alive will not die. That is, we will not be stripped of our bodies and become naked spirits, but our mortal bodies will be clothed with our heavenly, immortal bodies, and we, too, will be caught up to meet the Lord in the air.