It's been a long time since I saw this movie so I can't be absolutely
sure about this sighting. The 1951 filming of Ernest Gann's "No
Highway In The Sky" starring Jimmy Stewart. Jimmy plays a widowed
absent minded professor type with a young daughter. He works for a
British aircraft manufacturer, and he's convinced that their latest
airplane is flawed. I believe there are several scenes with Jimmy
working his slide rule for various calculations. The book and film
were obviously based on the de Havilland Comet (I believe the plane
in the movie was called the Reindeer and was propellar driven). Of
course Jimmy is vindicated in the end and gets a new mother for his
adolescent daughter. A very good movie.

Kurt