Thing about the chariot is that it, like Byrne's revamp, completely misses the point of the Invisible Plane. Yes, it's quirky and bizarre and kind of delightful in that insane Comic Book Way, but that's not the point, that's just a bonus. The point of the invisible robot plane was twofold: 1) keep the at-the-time-flightless Diana competitive with her flying allies and enemies, 2) demonstrate just how crazy sophisticated the amazons are. Because they can invent an invisible plane.
The first has been gratuitous since long before the revamp. The second still, theoretically, has some legitimacy, BUT... if you make it a gift? (And then, later, bizarrely, an actual living creature in and of itself, as Moore also hints at here?)
Then the plane has no reason to exist except to be quirky and weird, and that in and of itself is simply not justification enough for it to be in the mythos. Not even in comics, not at this point in the genre's evolution. Moore would ordinarily get a bit of leeway on the "parodying a famous trait of the source character" front, but if you're giving her a father, I think "but we're trying to hit all the important traits of Wonder Woman for this character" ceases to be a legitimate excuse.
I think the stuff that got carried over into Promethea, at least in terms of the cosmology, was less about "I have this cool idea, I want to use it," and more about "this is how I see the world, so I'm going to write it wherever possible." That was kind of his self-professed thing in writing Promethea, yes? The whole thing's didactic, a setting and perspective loosely disguised as a story.