Quiet supersonic flight is an intriguing idea. Is it possible? We'll see perhaps this year. I'd be curious about the cabin noise, as well as the external noise. Spike Aerospace expands quiet supersonic aircraft development Engineering is on track for a first flight of a subsonic prototype of the jet by late summer of 2017. http://www.aerospacemanufacturingan...quiet-supersonic-aircraft-development-012717/ Spike Aerospace evaluating engines for supersonic jet Two major suppliers being evaluated for S-512 supersonic business jet. http://www.aerospacemanufacturingan...pike-aerospace-engines-supersonic-jet-062416/ http://www.spikeaerospace.com/s-512-supersonic-jet/ http://www.spikeaerospace.com/quiet-supersonic-flight/ http://www.spikeaerospace.com/s-512-supersonic-jet/specifications-performance/ No endorsement expressed or implied.