John,

A Martin hardshell case is fine for most travelling, but for flying, I'd suggest something stronger. The Mark Leaf case is an example. You will find that luggage does not get gently treated by the airlines. In addition, your guitar will probably be exposed to extreme cold and maybe extreme heat.

There are many stories of guitars broken in flight.

Also, Phil's recommendation of not having "security" for your guitar is spot on. If your case is locked and they want to see in, they will break your case, so leave it insecure. If it you check it (and many airlines force you to check instruments) get to the baggage place on time. No one will be watching your guitar and oversized baggage is often placed in some out of the way places. In many airports, no one checks to see if the baggage you pick up is yours and someone could easily picked up your guitar.

Sorry for all the bad news.

Roger in Baltimore