Presumably, at TL12+, you don't really *need* aircraft. (At least where "aircraft" means "depends on aerodynamic lift and control surfaces to operate in athmosphere.") At some point, grav vehicles replace aerodynamic-lift vehicles for aerospace control functions. OTOH, aerodynamic control surfaces *may* allow tighter maneuvers than a a 6g brick might otherwise manage. Dan -- "Any sufficiently advanced parody is indistinguishable from a genuine kook." -Alan Morgan