Nimbo,
We are getting into semantics (and relativitey!!) a little here, but there is no such thing as "Apparent" weightlessness. You are either under one G or you aren't, and wherever you are in the universe, it is because of the sum of all forces acting on you at the time.
If you are subject to acceleration due to gravity, and an equal acceleration due to being in a plumenting aircraft, your net acceleration (in relation to the aircraft which is your current local environment) is zero.
Astronaughts experience zero G for exactley the same reason. They are in a parabolic trajectory, it just happens to have a radius bigger than the earth. Whether their weightlessness is "Apparent" or not is irrelevent. It has exactley the same effects on them as if they were in intersteller space (including relativistic effects such as time itself running faster!).