It will only break the sound barier, if he exceeds the speed of sound compared to his immediate surrounding, meaning: flying 800mph ground speed, and you have a wind of 200mph pushing you, means that relative to your surroundings you only fly 600mph; but, flying 600mph ground speed, with a 200mph counter wind, means that compared to your immediate surrounding, you are flying at 800mph, and have broken the sound barrier.
There is no passenger plane in operation today that can go over mach 1, or supersonic (the concorde and russian concord style plane don't fly anymore), and if they do, I'd say viduy...