3ds Max :: Retopology Places Connections Through The Object

I´ve been building an airplane. After sculpting in rivets and some detail onto the wing i wanted to retopologize to get a lowpoly. But the new surface doesn´t always stick to the original object, when i try to let it go around the whole object it connects the vertices through the wing instead of sticking to the surface. This usually happens when i start at the top of the object-i place loops around it and when i try to close them at the bottom it "steals" the working surface on the top and pulls it down.