I have all my models in a glass cabinet, that keeps them save from dust and accidents.
I have never ship models. But if I transport models I use a large piece of styrofoam, cut it to fit exactly in a box, make holes to fit the landinggear in (I build aircraft) and then secure to model on the styrofoam with cocktail sticks. This way the model is totaly fixated on the foam.
Since I have been using this way of transporting, I've never had any transport damage.