Robuta

https://www.ycombinator.com/companies/boom
Economically and environmentally sustainable supersonic travel. Founded in 2014 by Blake Scholl, Boom has 227 employees based in Centennial, CO, USA.
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https://www.flightglobal.com/aerospace/going-nowhere-fast-does-supersonic-air-travel-have-a-future-after-aerion/143920.article
Prospects for continuing investment in the sector come into question after pioneering developer runs out of cash
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