Lockheed Martin X-59 Quesst

The Lockheed Martin X-59 Quesst, short for Quiet SuperSonic Technology, is an American experimental supersonic aircraft built by Lockheed Martin for NASA's Low-Boom Flight Demonstrator project. It is designed to cruise at Mach 1.42 at about 55,000 feet while producing only a soft thump of about 75 effective perceived noise level decibels instead of a loud sonic boom, so that NASA can test whether quiet supersonic flight over land could be accepted by communities. NASA awarded the build contract on 2 April 2018, the US Air Force assigned the X-59 designation that June, and a General Electric F414 engine powers the aircraft. After repeated delays it began flight testing in late October 2025.