I'd like the invisible plane to be similar to the Bug, or Archie. An invisible, flying Batcave for Diana. It would be where she keeps her armor and weaponry, and a good spot for breathers in the middle of the fight, like she's got something that would save the day stashed in there, somewhere.
. . .
But, y'know, calling it an invisible robot plane just makes me want it to be like a Robotech/Macross Valkyrie or a Transformers PowerMaster (in Japan at least): a transformable mecha. That would warrant it being included in the WW mythos, surely. If anyone besides Batman or the Toyman should be in a big crazy robot fighter, it's Wonder Woman.
Aaron "The Mad Whitaker" Bourque; imagine the fights with Giganta! And as for the visual dissonance of tiny floating Diana several dozen feet away from whatever's fighting Giganta on her level, just have it only have stealth-invisibility only while in plane mode. Then we can keep the cool visual of the gerwalk mode! Yes. Loving this idea more and more.