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NASA, Lockheed Martin Reveal X-59 Quiet Supersonic Aircraft
(www.nasa.gov)
This is a most excellent place for technology news and articles.
"NASA aims to gather data that could revolutionize air travel, paving the way for a new generation of commercial aircraft that can travel faster than the speed of sound."
I think that is definitely just a cover because they don't want to admit they're actually developing supersonic stealth planes for the military.
Ftfy
What they reveal openly is usually from years ago. A couple aerospace friends are always like "yea, we heard scuttlebut about that about 5 years ago, so that means it was already a thing 10 years ago*, haha.
Well hiding the giant boom is probably a good stepping stone to that so yeah
From the eyewitness accounts of whistle blowers, traditional propulsion and modern propulsion are old tech compared to what they have today. Silent and extremely fast already exists.