erm, I *always* have to check my guitar into the bloody hold, I carry it in a hiscox flight case but I carry it to the plane and collect it from the baggage handlers at the other end, they won’t let me buy a seat for it, unlike those bloody cellists who ARE allowed to buy seats for their instruments.
If however I was prepared to carry my guitar wrapped in a stupid soft “case” then I would be allowed to bring it on board but in my experience those bloody bags only serve to make morons think that it is subsequently bulletproof and cram their ten thousand handbags in and around it leaving me with various dents and knocks to discover at the other end.
Why are you not allowed to carry a snowboard on as hand luggage? because it is not a fragile wooden box with high tension strings pulled across it, its a laminated board designed to be jumped up and down on!
(and you can buy hard cases for them too!)