 Stunt pilot, Derek Piggott, flew both Stachels and Von Klugermanns  planes for the bridge storming scene. With multiple camera angles  (including one from a trailing helicopter) Piggott actually flew  under the bridge over twenty times. To prove that the sequence was  real, sheep were placed in the field next to the bridge so that they  would scatter as the plane approached. However, as can be seen in  the continuity, by the 20th take the sheep had become blasé and  didnt scatter any more.