Weeeeeell... I will tell you what I know and what I assume regard seemingly contradictory posts in other threads here. Universal Creative props or an offshoot of that, is the lead vendor/contractor. While I know nothing of an aircraft manufacturer being involved as a subcontractor, it would make sense from aerodynamic perspective that they would need such engineering expertise for the extended wing, which is quite literally a sail... in hurricane central.
So, this leaves the actual dragon, or skin of the dragon, and as I have been told, it was built by UC props or an offshoot. What set me back a few days ago regarding its appearance was I was told by a member of UC that it looks "crappy" and that they are attempting to fix it... and that this is what these delays are all about. That is vague I know... what exactly is "crappy" about it?
I poked around to find out where it is being built... and all I could come up with was this conjecture: in one of the soundstages or in a section of B32, which is a very large building.