'Increasing the Charge' - how piston engine technology provided the power to fly

[Archibald]

Almost overnight the Whittle engine changed this and although we are again approaching a limit due to what may be called the heat barrier, I am sure this will be surmounted.

Hypersonics sucks: only makes sonic boom and heat barrier worse. Suborbital is the real deal. Go into space, no more air: no more heat barrier, no more sonic booms. Boost-glide, skip-glide, ballistic suborbital: ways to go.