My version of @Mattflat101's original Darkstar. I fixed the Mach counter and it will now display the most accurate speed of sound. This hypersonic plane can currently reach speeds of Mach 8 and requires more flight testing to reach high hypersonic speeds of Mach 10 and above.

I also fixed the engines. The normal engines emit purple afterburners as seen in the movie Top Gun: Maverick, while the scramjets are colored yellow.

LINK TO @Mattflat101's ORIGINAL DARKSTAR:
https://www.simpleplanes.com/a/psW512/SR-72-Darkstar

FLIGHT INSTRUCTIONS

Turn on engines 1 & 2 (AG1 & AG2). Take off. Once you reach the altitude in which where you want to activate the scramjets, shut down both engines (AG1 & AG2) then engage scramjets (AG3) for hypersonic flight. Level off at your desired altitude.

I prefer to fly this thing at altitudes of 120,000 to 140,000 feet. In order to make this aircraft reach speeds of Mach 10, you have to edit the XML modding of the scramjet engines (the secondary engines with Activation Group No. 3) and do flight testing.

Original aircraft credit goes to @Mattflat101.

Happy flying!