Right after Snoopy uncovers Woodstock from under one of the napkins when setting the table for the fake Thanksgiving dinner, he is holding the napkin that Woodstock was hiding under. As he jumps down in the next shot, the napkin is gone.
Soon after setting the table for the fake Thanksgiving dinner, Snoopy takes off his chef's hat and puts it back in his trunk. When he and Woodstock return to Charlie Brown's house, they are led back to the kitchen, and we see another chef's hat that Charlie Brown suggests that Snoopy would serve dinner with.
As Charlie Brown, Snoopy, and Linus are cooking the fake Thanksgiving dinner, we see a skillet on the back right burner as Snoopy spreads the butter on the toast constantly as it piles. In the next shot, the skillet has jumped to the front right burner.