@freemo I think about it a fair amount to be honest. When you think about it, the pilot is already submerged in a fluid. We just have to consider how the pilot is supported. Changing that fluid and working out how something will move in it would take some research but it could be interesting.
I think a problem that is always going to be there is the way that the human body works internally. Our organs will move independently, no matter how we might be supported in space. Our brain can be concussed quite easily if we are jolted. Working out how to stabilise our internal structure for that kind of travel would be quite the challenge I think.
@Nyoei The medium matters more than you think. The reason your brain pushes towards the back of your skull is specifically because you are supported in a chair, which exhibits a counter force.
Consider a person in a falling elevator, they expiernce weightlessness and their internal organs behave as if weightless as well. Yet they are accelerating at 1G. Meanwhile someone on the surface of the earth expiernes their internal organs being "crushed" by that same 1G force, although that crushing is well within tolerance.