Plane to start with.
If you figure out what kind of floats they are, and if they have a website, let me know. I give foam float companies a free link on my club website. Also SeaCommander floats, because they are so incredibly beautiful scale units, even tho the only two pairs I have actually laid eyes upon have crunched in hard landings.
I keep wondering if it would be good to fill a set of seacommander floats with expandable urethane foam.