If he answered questions with direct answers such as you state above and when asked specifically what the Thanksgiving plans were and he firmly stated that they were going out to dinner for Thanksgiving then to a movie (and nothing else) I would find him much more believable.
My personal experience with liars is when they are telling the truth they give a simple firm answer like yes or no, but when they are lying they tend to give you a word salad...way too much information in much greater detail than is necessary and often times they change the subject and ramble on about something totally irrelevant. This has been my personal experience while dealing with those not be truthful so this is just MOO.
So you would feel someone who answered with word salad was more likely to be a liar than someone who answered questions with the same story over and over as if memorized?