I've got a Martin Back Packer. Not great. I've sanded down the saddle a bunch just to get the action more reasonable, but it's pretty much a 2X4 with strings. It works to keep your fingers limber, though.
I think my next try is going to be a Travel Pro. If I ever get a Travel Job again . . .
I was impressed by the full size fretboard of the model I bought, which was an electric model called the "Speedster". This is nice so you can practice on a full size fretboard unlike other models out there with a shrunken fretboard. They also make very small amp-device which plugs into the side of it....you plug a headset into this device and it is like listening to a big amp, all right in your hotel room. Not even the maids here a thing, it's awesome.
It has a black soft case it comes with and fits right into the back pocket of my old Purdy Neat Stuff bag. Security gets a kick out of it.
I am just an amateur but a few guys I have flown with are very good guitarists and they tried it out "on the ground..of course"....they were very impressed. I have not regretted that purchase one bit. You may find them up on Ebay....they seem to hold their value very well. Traveler Guitar makes several styles...I haven't tried the others.
I dont know much about guitars...but I started watching this show called shark tank. They had someone on there that invented a guitar that folded in half. It was made for traveling. It would fold in half and then lock back in place and still be in tune.
Like I said, I dont know much about them but it might be worth looking into.
I have the Martin Backpacker. No truss rod, had to shave the saddle. Sounds kinda like a ukulele but it does the job. OK for practice or to sing Kumbaya around the campfire. I like it because I can also play a harp with it.
I also have a Hohner (Steinberger) GT3 which is smaller but heavier and seems more awkward to carry. It also requires an amp of some type but it's a great guitar. I use a HeadJammer head phone amp. Stays in tune remarkably well. I'd even gig with it but I'd have a backup.
I've been using a Traveler Speedster for several years. Decent guitar with a 24" scale length, so it's pretty good to play on, especially with slightly heavier strings to counteract the shorter string length. A friend of mine just bought one of the newer models from Traveler called the EG-1 and while it's shaped like a Les Paul, it's got a Strat's scale length along with a built-in headphone amp.
If I was in the market for a travel-sized electric guitar, I'd go the EG-1 or EG-2. If you want an acoustic, the Baby Taylor is great and sounds a lot better than many of the smaller travel-size acoustics though it is a bit larger.
I have a taylor baby. Been happy with it for the most part... it feels and sounds much more like a real guitar than others that I have played. It even holds its own when jamming with its full size brothers. All that being said, go out and play a few and figure out what you like for yourself. Everybody is different when it comes to guitars.