In July, Lockheed Martin completed the build of NASA’s X-59 test aircraft, which is designed to turn sonic booms into mere thumps, in the hope of making overland supersonic flight a possibility. Ground tests and a first test flight are planned for later in the year. NASA aims to have enough data to hand over to US regulators in 2027.
Everyone was developing them, more or less. The thing is, the enemy doesn’t usually share their tech with you so you’ve got to develop programs independently.