MSL, AGL? And what if I'm in a plane at 900m MSL (Score 1)

Well, first off if the question the question does not secify what sort of altitude. AGL, MSL, or perhaps desnsity altitude? Who knows? If it is refering to AGL then most everyone is either airborn or 0m. If it is MSL then one could be at various altitudes. Secondly if someone is airborn then they are airborne and also at some altitude but can only pick one answer.