The Concorde was definitely supersonic. That was the whole point of the aircraft to enable commercial supersonic travel.

It's weird to see people continuing to argue about this, when the article itself makes pretty clear that this is about the subsonic record. Concorde and Blackbird are completely irrelevant. Of course they're faster, but that's not the point.

The entire reason a subsonic flight could go at speeds normally only possible to supersonic aircraft, is because of the speed of the jet stream driven by Ciara. The plane is flying at subsonic speeds within a moving pocket of air that adds quite a lot to that speed. That's the interesting part about this story.

Indeed, the airspeed/groundspeed distinction continues to confuse people. The plane still moves at subsonic speed, as that's w/r/t surrounding air.

I think there was some confusion on what the "this" keyword is referencing in the comment (one of the reasons I hate it in code :))