Word to the wise: Mail the guitar to your destination. Seriously, it beats the hell out of flying it.I just got another Martin in the mail, from South Carolina to Alaska, for $57. Express mail, 2 day delivery, FULL INSURANCE, and free if it didn't get here within 48 hours.
Be sure to loosen the strings about 3/4 octave, then immobilize the headstock and protect (or remove) the endpin. These two parts are the source of most guitar breakage woes, the headstock by breaking off when jarred, and the endpin for splitting the endblock if it happens to be dropped at the right angle.
Back to the flying issue, I flew Hawaiian airlines recently (I had a GREAT vacation, thanks for asking) and I saw a band bring all their instruments on board for the flight from Honolulu to Seattle, electric bass included...so go figure, it seems to depend upon the whim and world outlook of whichever harrassed airline employee you happen to deal with.