I could see you doing a mix of materials. 3D for detailed items and a main skeleton, along with cardboard and modeling paste to be the flat or semi-bent panels on Dropships.
Another idea might be trying to map the interior of a Dropship, and use the Dropship model to carry your Mechs as well. Each level can lift off a lower level, and has several hex-shaped depressions to put your Mech models in.
Very nice setup.