I fixed some stuff but it flies pretty bad and overall just feels like crap. So I don't think I'll be updating this
You said the aircraft's top stable speed was Mach 0.78, or 599 MPH. Mach 1 is 767, which is the speed of sound. Was there any effect when you went over mach one or did nothing happen?
BeamNG uses it's own physics engine, so if we were to have sonic booms, it'd have to be implemented with that. Probably one of those extras we won't get to enjoy any time soon since it's not really that important.