Well to tell the truth I still kept my eye on him and it did appear as if he was stroking a cat or other small animal. I figured if I chatted with him, I'd get a better sense if he was just a nervous flyer or pet owner rather than a terrorist reaching in his bag to detonate a bomb or something.
Its hard to describe his nervous/odd behavior, but I've not seen anyone act that odd. However, it could have also been my wild imagination.
I asked that too - about the cat. I told him my cats would be freaking out - he said his cat is pretty laid back and has flown with him before - the cat just does not like the subway. He said he was traveling for the holidays and didn't have anyone that could take care of his cat.