[Doug]

I've checked my guitar a number of times with no problems - I'm looking around now for some wood to knock on - don't want to tempt fate. I've never tried to carry it on - just assumed they wouldn't let me. I'll try next time.

Some people loosen the strings but I read (I think on the Larrivee site) that it is not a good idea to loosen them. The neck is much stronger when it has the tension of the strings (apparently) - in any case, I've never loosened them.

These days they don't like you to lock baggage that gets checked in. You could try "locking" it with a cable tie - that way security can snip it off if they want to inspect it. Of course, so can any one else, but at least it's a bit more difficult.
Another suggestion is to pack a bunch of socks in and around the neck to keep it cushioned.