I tried to look for other meanings of 'vane' not related to aerodynamics (weather vane, vane of a feather, etc), and I wasn't really successful. Oxforddictionaries.com gives an example of adjective as 'three-vaned windmill'.
But dictionary.com drops some examples which definitely stray from the definition, which doesn't touch them:
So it's vane to talk about blood since it's wrong to judge national background on this single factor.
He's a bombast anyway, a vane orator, the way so many pol's are.
These definitely don't relate to the given meanings which literally or figuratively refer to something affected by the wind.
What does it mean in the examples above? What other meanings does (or did in the past, archaic/obsolete are okay) this word take that are not direct derivatives of the primary a blade, plate, sail, etc., in the wheel of a windmill, to be moved by the air. ?