Well nobody knows for sure, the name Hiram J Hackenbacker was revealed in the episode "Alias Mr. Hackenbacker". Allegedly he was using his real name as an alias, but that presupposes everyone knew him as 'Brains' and that it wasn't a double-bluff.
All we do know from that episode is that air safety is appalling in 2068. In fact all H&S appears to be forgotten in 2068 as buildings and bridges collapse, monotrains run out of control, planes crash and blow up, rockets explode, giant mutant alligators roaming around, even the frickin' seaweed explodes tankers!
The JT1 Condor (known as the Condor XL6 in Supermarionation Cross-Sections, and simply called Jeff Tracy's two-man jet in Thunderbirds FAB Cross-Sections) is Jeff Tracy's personal aircraft - a supersonic/VTOL/delta-wing jet. It's featured in Atlantic Inferno. 1 Technical Data 2 Cross-sections...
This jet has a remarkable resemblance to a Shorts project featured in Tony Buttler British Bombers Projects. I attach a bad copy.