To everyone who thinks it should be a simple matter to take some off-the-shelf aircraft designs and technologies and produce a new supersonic trainer, I offer the following: In 2020, the Air Force mandated that companies must design future aircraft to fit a wider range of recruitable Americans, rather than past standards based on a 1967 survey of male pilots that considered their standing and sitting heights and reach. The 2020 requirement is to safely eject persons weighing between 103 lbs to 245 lbs, with varying cgs, from zero altitude to 40,000+ feet and zero airspeed to 600 knots IAS. A friend of mine ejected from an F-4 at 500+ knots, and broke all the major bones in both arms and both legs. He took years to recover, but he lived. This seat is required to handle that situation without injury. There are many stories of aircrew who suffered spinal damage from ejection seats and even from ejection seat trainers. The seat is only one of the requirements that previous trainer aircraft have not had to deal with. As long as unobtanium remains one of the services’ requirements, we can expect “once proud” aerospace companies to experience development and testing delays.