Dan, good comments.
I think wheel size is also a factor. I used to travel a lot for work. Considered buying a folder for that. And read an article about the Airnimal Joey where they were saying that it felt as good as riding a full size bike with the larger 24 inch wheels. I decided to buy a Joey frame and fork, and build it up for travel. And immediately after that, I got a different job, was not getting on airplanes many times a year for work any more. So, that was a wasted effort.
Then, tried to buy the suitcase for the Joey. Could not buy it in USA. Then I learned that British Air at that time had a more lenient policy for luggage size than USA airlines. And that article that sold me on the Joey was in a British publication. So, suddenly I had a folding bike that was too big to fit in USA sized luggage. At that point, if I could have easily sold it, I would have. But it really had no great advantage to a potential buyer.
Then years later, I had bought my S&S coupled Nomad Mk II, had traveled with that, came home from one trip and I was looking inside the empty S&S case thinking that it was a huge amount of space. So, I tried to put my Airnimal into it, and it fit. Took a lot of work, had to remove fork and crankarms, but it fit.
Then, in 2017 went on a trip with two friends on an ACA van supported trip. This means every day we would be riding bikes, but not carrying any gear. Thus, road bikes were the ideal choice.
The other two people that i was traveling with packed their full size bikes into boxes to be shipped by BikeFlights, that is more convenient and cheaper than carrying a bike on the plane. I planned the same thing, got a bike box from a bike shop. Then less than a week before the trip tried to pack my titanium bike in the box, it would not fit. Could not find any other bike boxes in town.
Crisis. (This was before I bought my Ritchey Break Away.) So, had a choice, which bike do I put in the S&S case to take on the plane. Decided to take the Airnimal. It took almost as much time to pack as packing my Nomad MK II in the case, but it did work out well.
I was quite pleased with how my Airnimal worked on that trip. It handled very well, especially when you consider that everyone else in the group had road bikes or a few had touring bikes.
First and second photos, the bike.
Third photo, one night we stayed in a motel, it was easier to carry my Airnimal up the stairs using the first fold than unfolded, so I did that, it was also more convenient to store in the room that way.
Fourth photo of me walking out of the airport, wearing the S&S Backpack case with my Airnimal, wheeling my other carry on and carrying a carry on bag. The S&S case is hard to see being black with a dark background, but it was easy enough to carry the bike that way.
In summary:
I think the Airnimal rides as well as a full size bike, I credit the 24 inch wheels. The front wheel has less gyroscopic effect, so steering is a little faster. And the tall seatpost extender has some flex that took me a while to get used to. But otherwise it worked great.
But the Airnimal is too complicated to pack, takes to long. But I can see a 20 inch wheel folder being a great traveling bike if it can be packed in the case a lot faster than the Airnimal.