Mike McCarey told our class to put them in a plastic bag with a pipe cleaner to close it up. It does really help, much like the box/bag suggestion above. It is difficult when there are delicate decorations on the cake. You can chill it for a while and then put in a bag to reduce on the boo boos. We always chill our fondant and deal with the condensation. I will only travel with a cold cake. It’s not the fondant that is giving you the problem, it’s the temperature and humidity. Best of luck!
Jenniffer White, Cup a Dee Cakes - http://cupadeecakes.blogspot.com