When I saw the Thunderbirds at an air force base in the 1970’s, they did at least one supersonic pass. It was an incredibly scary experience. I was looking around for the plane, and I turned in one direction, and there is was, streaking towards us seemingly only a hundred feet or so off the ground - totally silent. It gives me goosebumps as I type it, when I remember how it felt to see such a fast, powerful, deadly device coming towards us silently.
I guarantee that was not supersonic, just the standard sneak pass I described above. For an observer on the ground, the planes are virtually silent in that high speed approach, but the fact that the sound doesn’t precede them doesn’t mean they’re breaking the sound barrier. I don’t think even in the 1970s there were any supersonic performances at airshows, and certainly not at low altitudes. The potential for serious harm to people’s eardrums would be far too great.
My one and only supersonic flyby was done by an F14 streaking over the carrier I was stationed on, in international waters (off Singapore, as we were doing a “dog & pony” for visiting dignitaries).
But I had the same goosebump reaction. How can something so big, moving so fast, be soo silent? It was almost counter-intuitive.