The Aero 2536 "Catalina" is a sci-fi flying boat concept.
It is a spacecraft3 vessel and as such requires the spacecraft3.dll file.
For more details see readme.txt in the linked catalina.zip file.
[Haters never change, but I can genuinely see how the mesh would look "alpha quality". Will see if I can come up with something a bit better in the future given experience/hardware/engine.]
14/03/14:Aero 2536 mk II "Catalina"