if you fold the bear hide in any way shape or form you will get hot spots and the hide will get ruined for sure.

If it were me I would flesh the hide as best possible then cover it in salt and ROLL it up and pack it in a suitcase, the under belly of the plane should be cold at higher altitudes.

You could get a more solid answer down in the taxidermy column though. Get your ducks in row before the fact so you won't ruin your trophy, good luck.