> Supersonic flight has much less overlap with subsonic flight than you might think.
And every supersonic aircraft also has to fly subsonic. So you really need two sets of software in a supersonic aircraft. Or more accurately three, because the transonic regime is weird enough to be its own thing.
What about the airplane given in the original example, the F-100, whose design predated the integrated circuit by something like a decade? Presumably control software improves stability, but otherwise the aircraft behaves in a predictable manner above and below Mach 1 as supersonic control software is a relatively recent addition.
And every supersonic aircraft also has to fly subsonic. So you really need two sets of software in a supersonic aircraft. Or more accurately three, because the transonic regime is weird enough to be its own thing.