The claim sorb appears to have been judged as false. I believe it is true.
The only flying aircraft that can do mach 2.5 are military and I would suggest not transport as in having a paying customer, which was suggested by claim creator.
There are lots of sounding rocket used for research and these often are operated for fee paying researchers. I believe they often meet the required speed and don't use locally available gasses.
So some suborbital exceeds zero high-mach air transportation.
The claim should be discussed and considered rather than just being judged false.
disclosure I had over +4000 holding source