Why is commercial air travel still the same speed it was 60 years ago? And will it ever change?
In: Technology
[Because transonic drag (Mach 0.8-1.2) is awful](https://upload.wikimedia.org/wikipedia/commons/0/0e/Qualitive_variation_of_cd_with_mach_number.png)
Around 80% the speed of sound the drag on the plane starts to skyrocket, going from 80% to 90% can be a 3x increase in drag which results in a 3x increase in fuel consumption which results in a massive increase in ticket cost. Once you get beyond about Mach 1.2 though drag starts to drop off.
This region between Mach 0.8 and Mach 1.2 is the transonic region and its when some of the airflow is supersonic (pinch points and tight curves on the plane) while others parts are subsonic and it creates this real mess. This is why planes either fly well under Mach 1 or well over.
Jet airliners have been running in the Mach 0.75-0.85 range for over 60 years now, that’s as high as they can practical go without breaking the sound barrier which is a no-no over land, that’s why they’ve instead been focused on fuel efficiency to reduce running costs
There is research into Quiet Supersonic jets but its still quite experimental and a few decades off. Until we can get rid of the damaging sonic boom overland flights have a pretty firm limit at Mach 0.85
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