How do i make a clean plane Script?

I'm trying to make a script when 180 seconds is up a script will wipe out all planes that don't have anyone on the seats. I also want to mak it say 185 seconds before it cleans them. Please help fix this script.

messageText = "Plane Cleanup in 3 minutes"

game.workspace.Plane.Child.Plane = 'Plane'

wait (5)

do message.Text = messageText("180 Seconds until planes cleaned")

do wait (180)

remove='Plane' if

workspace.Plane.humanoid.found then

remove=false

end

end

in pairs