Good for this guy, and I will believe because he had witnesses, but something I learned from a professional musician, who learned the hard way, packed his gold top Les Paul, in the hardcase fully strung and tuned. The flight was well over 30,000', when he arrived the atmospheric pressure affected the wood and with the strings tight, snapped the neck. Always destring or really relax the strings when shipping by air.
I would be really sick if that happened to my Taylor, K22C.