Seriously, I always transport my cakes/ccs with a piece of the shelf liner underneath it. The kind that is made of rubber/foam. It's got a good grip and I never have any problems. I'm sure someone else has a better idea, but this always works for me.
I've transported cupcakes in cake pans... then placed that on the shelf liner in the car so that they don't slide. I do recall seeing online special cupcake boxes that have a liner with the holes in it to keep them from tipping/moving, I don't recall where though
always get the aluminum platters (14" ?) from costco and they have lids. Each holds about 25-30 snugly so they don't shift and you can stack them if you put that non slip mat stuff in between and underneath. i have never had an issue!!
I have also seen on a post here where someone used those aluminum cupcake tins ( not the individual one, but just like cupcake pans only disposable) and glued them to a big box. that held each cupcake in place and usually fruit/produce boxes can be stacked.