What happens when the person in front of you shifts around in their seat, do the tiles bounce around at all? I'd be afraid to have an hour of tiles get jumbled up.
No!
Because of the felt they stick very well. It is more a problem to get them away from the ground of the box after a game
If you don't play with the aditional plates, you can interrupt the game, put the box together (with the small wooden meeples on it) and continue later without getting only one of the tiles lost. That was important for me, because that sometimes can happen while traveling.
And one thing that I see as a slight problem: the weight and bulkiness of the box. Makes me wonder if you could print the tiles onto those soft plastic sheets that stick to anything with static electricity. They would only weight a few dg, and you could just use the trays as one continuous playing surface!
Ok, the box is not as small to put it into your jeans pocket
But we had it for four times in the handluggage (normal backpack) in the plane and two times in a train and it was no problem - what else is important to have in the handluggage? Maybe a book, some paperstuff, some warm clothes, that does not steal much place in the backpack.
The version of the magnetic tiles is also interesting.
http://www.carcassonnecentral.com/forum/index.php?topic=728.msg9552#msg9552But the size of the tiles is too big for me, if playing with 2 basic games and the 1st and 2nd expansion and the lake you would need to carry a bonnet with you, the security at the airport may not allow that in the handluggage