Since I've noticed is thread has plenty of views and for completeness sake, I want to write how I managed to get such a large board on board a plane...
I was flying from Miami to Cancun on American Airlines. It was surprisingly easy to get the board on the plane... I just let the guys doing check-in on the sidewalk handle it! They do charge a small fee, but they know how to handle things and to which airline representative talk to, the lady at the counter didn't as much a bat an eyelash when he saw the humongous board!!! I even tipped the sidewalk guy, it was definitely worth it.
Make sure you get a nice travel bag and that you protect your rail, bottom and mast track with extra cardboard and bubble wrap the nose and tail, also be aware they the airline will charge a substantial fee for taking the board...
Good luck on your travels!