"The dead in Christ shall rise...."

But what is the biblical standard of death? "Leave the dead to bury their own dead, and follow me".

Regarding the scriptures about the dead rising in the air:

Rev 17:15 Then the angel said to me, “The waters you saw, where the prostitute was seated, are peoples and multitudes and nations and tongues.

The "waters" here is a symbol of people, of multitudes.

What happens to water when it evaporates? It purifies, and becomes clouds.

Heb 12:1 Therefore we also, since we are surrounded by so great a cloud of witnesses, let us lay aside every weight

A 'cloud' of witnesses. Here, again, 'cloud' refers to people.

When scripture says that Christ returns on the clouds, it does not mean that Christ will return in the sky, up at the stratosphere, but rather, than when Christ returns, his return will first of all resurrect a number of people and purify them, and then surrounded by them, Christ will then reach out to all the world.

Rising into the air can easily be understood as a metaphor for spiritually being elevated through unity with Christ when he returns.