I can't see this happening. What we now know as the Air will be phased out. The MacBook will be the only consumer line, available in two sizes and known either as the MacBook or the MacBook Air.
Looking into my crystal ball, I see a 12" and 14" MacBook and a 14" and 16" MacBook Pro, thinner and taking design cues from the current MacBook, having a thinner bezel and similar footprints to the current 13" and 15" MacBook Pro.
Looking into my crystal ball, I see a 12" and 14" MacBook and a 14" and 16" MacBook Pro, thinner and taking design cues from the current MacBook, having a thinner bezel and similar footprints to the current 13" and 15" MacBook Pro.