As long as you don't have a big carry-on bag, you should be able to take it intact onto the plane.
On my last trip to America, I brought onto the plane the Kreo Devastator Vs Ironhide set because it was too big for my check-in box, and I didn't want to destroy/damage the Kreo box. But I got there early enough to repack its contents into my backpack if they stopped me.
If you keep your backpack really small and insignificant looking, they shouldn't have a problem with the size of the toy box (even though they say that carry-on items should fit in that small guide-frame at the departure gates). It's only a thin box, so if you carry it under your arm like a book (to not draw attention to it), and stick it flat in the over-head compartment (and make sure nothing too heavy sits on it), you should be able to keep the fancy box intact.

Dimensions -
Kreo box I got on with no one questioning me - 61 x 36 x 9
Reissue Omega Supreme box - 55 x 37 x 9
(it might be more eye-catching to draw attention to it, but is smaller than the one I took on board, so shouldn't be a problem)

BUT - just get to the airport with enough time to to unpack the contents into your backpack if for some reason the check-in desk attendant says you can't take it on. (ask CASUALLY if it is okay) This way, you have a back-up plan if for some reason they say no.
Considering the size of stuff I've seen people take on the plane, you shouldn't have a problem if your other item (backpack) isn't too big (remember, you are needing to leave enough space in your backpack to repack the toy and folded up box if they say no... which will make it small enough to be okay).

(perhaps even wrap it in paper or plastic wrap too, to protect it from scuffing... and make sure you don't put batteries in it before you fly)