 In the end when the family is climbing over the hills to safety, it  is not really Gretl on the shoulders of Captain von Trapp. In the  DVD version, it is revealed that while in Austria, Kym Karath (qv)  gained a lot of weight. This was one of the last shots filmed and so  she was evidently a bit too heavy to be carried on  Christopher Plummer (I) (qv)s back. He requested a stunt double  and that is whos seen being carried on his back.