system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are planes not getting faster?

Technology advances at an amazing pace in general. How is travel, specifically air travel, not getting faster that where it was decades ago?
gpt
Passenger aircraft fly around 85% the speed of sound.

To go much faster you have to break the sound barrier, ramming through the air faster than it can get out of the way.  This fundamentally changes the aerodynamic behavior of the entire system, demanding a much different aircraft design - and much more fuel.

We know how to do it, and the Concorde did for a while, but it’s simply too expensive to run specialized supersonic aircraft for mass transit.