Large 3d object view problem

Hello, i want to build an AR app where the main idea is to scan an image target and appear a huge 3d object like an aeroplane(30m length) or buildings or anything else in real world size..When i import my 3d object into unity the scale is like x=1 y=1 z=1 but my 3d object dimensions are much bigger..So i change tha scale and make it bigger but when im running the app not loading properly(I can see only some parts )..So i want to make the object appearing far away from my camera(to have the view of whole object) .Have an idea about that?..Is there someone who dealing with realistic size 3d objects like ferry boats or aeroplanes or anything else?