Despite all these technological advances, a supersonic aircraft still cannot beat physics. Shock waves, and their associated drag, will still exist. So, a single supersonic aircraft will still produce considerably more carbon emissions than its subsonic counterpart.

The last time anyone other than a fighter pilot went supersonic was 20 years ago. Today, you can only visit a Concorde in a handful of museums. It's a relic, left behind by an industry that invested in efficiency rather than speed.