^^^ This is how most keel boats store all their sails and as long as you don't press the creases in won't do much damage if done once. If you want to protect the sail even more. Lay an old quilt or blanket on it and fold it up with the sail. This will stop the creases being flattened.

Second thought what does a return flight to the mainland cost? You could always check it as oversize luggage.

^^^ This is how most keel boats store all their sails and as long as you don't press the creases in won't do much damage if done once. If you want to protect the sail even more. Lay an old quilt or blanket on it and fold it up with the sail. This will stop the creases being flattened.

Second thought what does a return flight to the mainland cost? You could always check it as oversize luggage.

Can you get away with putting such a package on a passenger plane? Maybe you can find someone who is flying to Hawaii and would be willing to check it in as baggage. I wonder how much that would cost.

You can definately take a sail on a plane, you just need to check it in with the surfboards etc at the oversize counter.

I've thought about using a hard ski box for bringing sails on a plane. I'd I did the euros, I wanted to use my sails, it seemed like the best way to do it. Not sure if there's a long enough box available though.

Jump skis are 2.5m that should cover it.

After talking with the local sail maker, I ended up folding it once down the center and rolling it very loosely taking a lot of care to make it as flat as possible before rolling to avoid any places bunching up and creasing badly.