The problem is the acceleration/mass when dropped. Therefore you must weigh rigidity (resitance to being crushed) against inertia. Cardboard plus bubble wrap I believe has the best combination. Flight case is good of you think it will go in with heavy cargo, but that is unusual for luggage type travel Carbon case, or injected plastic are good options, but cardboard is tried and true for shiping. Larger boxes are vailable as "wardrobe" boxes from U-Haul. dt
To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
