A musician friend I know was about to head overseas and originally just planned on checking his instrument. However, another musician he knew had taken a similar trip on the same airline recently and his $18k bari sax had been crushed and bent in half inside its case.
My friend ended up buying a plane ticket just for his horn.
Last summer, we took a band down to Brazil from our church for a worship trip. We ended up taking on several guitars onto the plane as carry-on's. Checking those things would have been disaster. I didn't take my own Larivee on that trip. We ended up leaving many of the guitars there for the churches. If I ever take my own guitar on a trip, it's going with me as a carry-on. Too expensive to check.