I went to a hammered dulcimer gathering in LA many years ago. I had a chessmen bridges dulcimer - that is each bridge was separate - it was fully chromatic - made by Geoff Giddings. Each note had 4 strings. It was a sod to keep in tune.
Anyway I caught a BA direct flight to LA from LHR. All was OK and I was allowed to carry it on board. The crew stowed it in the 'secret' cubby hole used their own personal effects.
It arrived carried by hand into the arrivals hall. It only required a little retuning when I got to my room.
The gathering at UCLA was great. American dulcimer players had not seen the East Anglian chessmen type before.
However the journey home was a nightmare. Firstly it had to be x-rayed. US scum TSA wouldn't listen that it was a delicate musical instrument, despite Fragile labels on the case. They banged it around. Dropped it. Wouldn't believe there was nothing inside the body. They wanted to take the strings off and take the sound board off. Eventually they accepted it as was, but then BA check-in staff refused to allow me to carry it onboard. They put it on the luggage belt - where despite the Fragile labels on the case - it must have bumped and banged around the luggage belt system to be loaded with all the cases and God know what into the hold.
So we arrived back at Heathrow. Again it was put onto the baggage belts. B'stards. Anyway when it eventually resurfaced into the arrivals luggage hall I opened the case and every f'ing string was displaced, and all the chessman bridges had moved. And some of the bass strings were broken.
It never went travelling again.