All the travel guitars I've seen are too big to put in an attaché case - they tend to be the same length as a small ordinary guitar, though nice and light. Great for walking around up hills. I've got one I bought one year at Whitby, where all the roads seem to be uphill - in both directions. Great fun to play, and lovely to tote around, and quite a nice sound. But it wouldn't fit in the kind of case you can take on a plane.

The only one I've seen is one I bought a few years ago in a charity shop. A small guitar, but the thing is, the neck is fastened to the body in such a way you can detach it, and then you can fold it up and squeeze it into a small case. Needn't even take off the strings. It's a bit of a pain getting it reassembled and properly adjusted, but if you were making a single plane flight, and then getting around in other ways it'd be a fine solution. And it has a sweet tone - since it's got a shortish neck I find it responds better tuned two semitones high, so it's F#BEAC#F#. (Though it sounds fair enough in standard tuning.)

I've no idea who made it or how long ago, though I'd say a good few years ago from the look and feel of it, but I think that's a very practical way of dealing with a nasty problem. Easy enough for a guitar maker to build, and I think there'd be a fair niche market for them, but there doesn't seem any sign on the net of someone having produced something like that.