It's a state of complete freedom from thought.... but the mind is not a blank, but pure, clear energy, blissful, exhilerating, and utterly focussed.
I don't know specifically about flying through the air or all that, but a bit about sword fighting. There's a greta book - unfortunately only in German - called Wunderbare Katze which would be helpful to you to read.
Though all these cultures use different terms to describe it - qi, chi, prana etc - they all refer to the same thing.