Replying to Bringing Your Guitar On A Plane?

Hey I'm going out to Whistler this week with a bunch of friends and I really want to bring my guitar. It's a Martin acoustic and I really dont want to fuck it up. I hear that guitars can get messed up while on board from either the altitude or the lack of pressure. I might try and bring it on as a carry on, but I'm not sure they will let me, I will probably call. Anyway, has anyone ever had any problems with this? let me know.
Thanks.