If you get a new kitty soon enough for them to bond with each other, it may actually be LESS stressful for them because they would have each other. Now for the argument that they may NOT be getting along, I feel it could not be any harder to transport 2 than it would be to transport 1. After all, any one of us who has multiple pets would not leave some behind because we had to move. (stating it in other words, if you already HAD a second cat BEFORE you thought about moving it would not even be an issue..........if you see what I mean)

So go for it !!!!!!!!!!