Ah, cool.
As a complete aviation nerd, the first codenames that came to mind were Prowler and Growler. I'm not 100% sure if there's any overarching theme you'd like us to conform to (aside from avoiding anything obviously unfitting, like "Daisycakes Flufflecup the III"), so it's kind of a little difficult to think things up.
Other ideas that came to me are Vulcan, Hellraiser (though that might be a touch OTT), Spartan, and Dragon. Perhaps Gargoyle might work, too, or possibly Windstalker since it's a hover tank?
This is all off the top of my head, so I apologise if they're not what you're looking for.
Anyways, I'm working on a post now - I should have it up either tomorrow or the day after.