I took a mini Martin to the BVI last year.

Seaborne absolutely would NOT let me take it into the cabin although I know darn well that it would fit.

So it ended up in the back of the plane with the rest of the baggage.

So there you have it first hand.

FWIW, Taylor makes a similar guitar that you can easily remove the neck from. Put the neck in a suitcase and make some sort of rigid case for the body.