I've flew to Russia, Azores and Brazil with several instruments, within orchestras and a Big Band. When arriving to Russia, we saw the guys taking the cases off the airplane. We even made a film that served as evidence for insurance. Probably 60% of the instruments where damaged (or their boxes). Luckily I wasn't carrying my bass, I was with the clarinet. But I saw tubas, an accordian, saxofones, etc, all in proper flight cases and with TONS of fragile stickers and the guys where throwing them away off the airplane into the land transporters (no treadmills)!! From that point on, I always carry my bass in a gigbag, with me into the cabin. I never had to buy an extra seat or had to pay extra money. I just put it in my back and never asked anything to anyone. Last month they made me put it in the scale to see its weight, but that was it. I never flew low costs with it. I always try to get a proper airliner when travelling with my precious…
To Brazil we bought some space in a container. At the end it was a whole container for the big band. You know those containers, with the side inclined to fit the airplane cargo area?... A guy just brought the container to us in a forklift thing, in the check-in area in Lisbon airport. We loaded it ourselves. And when we arrived they brought the containers to us to unload. Everything was untouched! That was the only time I flew with my bass in the cargo bay. I have no idea how much the container costed…
But I’m going to check that extra seat option, in case I need it. Seems a good thing to do!