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.

NASA is pushing the boundaries of supersonic travel with its experimental X-59 jet, a sleek, needle-shaped aircraft designed to fly faster than sound—without the disruptive sonic boom. The agency recently completed crucial engine performance tests,