I remember that when it came time to film A Bridge Too Far, the film company had several Horsa gliders built from the blueprints of the originals. They went to the BritishCivil Aviation Authority to get them certified so they could fly them and the CAA flatly refused, saying that the gliders were too dangerous to all concerned to be allowed to fly in peacetime. As a result, they had to tow them up and down the landing strips and shoot pictures that suggested they flew for the film.
Bob