The Ordeal of Flying Itself was Traumatic.
Despite the fact that it is difficult to keep track of one’s location when flying, this gentleman had managed to persuade himself that he was on the incorrect plane and travelling in the improper direction. There is no rational justification that can be given for his behaviour.
If this were the case, he would have been aware of it as soon as he went through the security checkpoint, or at the very least, when he inspected his boarding pass. Everything went back to the way it had been before the man had the opportunity to process what had just transpired in his life and had some time to think about it.