If this is about a specific war / revolution, it's not clear which one it refers to. However, the 'hidden meaning' here is the 'dancing on air' lyric. That refers to being hanged. "I saw an army of rebels dancing on air" means he saw them all being executed by that method.
If this is about a specific war / revolution, it's not clear which one it refers to. However, the 'hidden meaning' here is the 'dancing on air' lyric. That refers to being hanged. "I saw an army of rebels dancing on air" means he saw them all being executed by that method.