I've always thought that we will never have unmanned
airliners, however if we make the next step to sub-orbital hypersonic regular public transport - then that might also include full automation.
Just as in today, you get onto a roller-coaster, staff help you strap in and check you're safely secured - and then they get off and you go for the ride, trusting to the design.
It wasn't always that way - roller coasters used to have "
brakemen" riding on the coaster to control it - no one thinks twice that they aren't there now.
I could see a hypersonic flight, taking an hour or less, working in the same way.