Hey Stagger,
"True super-sonic travel" was in reference to the near super-sonic travel of the Sonic-cruiser. But, I'm sure you knew that. Oh ya, my old 454 Chevy Impala was feasible when it came out in 1970 as well, but with the cost of fuel these days it's costing a pretty penny and I don't have to worry about environmentalists..........yet!
See ya!