I’ve been stung at least once with charges for transporting my snowboarding gear on a flight; actually it was a two-leg flight with KLM, and I’m pretty sure I ended up paying the charge for both legs, in both directions.
Anyway, a friend pointed me at this table that airport parking company APH have, which summarises the charges with different airlines for taking your snowboard. It might be useful…
You’ll also find that you pay less for smaller snowboard bags. This is a little bit annoying for us larger riders. To be absolutely sure of your size, use our snowboard size calculator available here https://www.snowboardingdays.com/snowboard-size-calculator/