Jimmy Stewart knew anything about flying?
He flew combat missions in World War II and retired as a brigadier general in the U.S. Air Force Reserve in 1959, according to IMDb.
So, this role as a "dorky" aeronautical scientist in No Highway in 1951 is kind of a moviemaker's "in joke".
E pluribus unum
I hardly think "in joke" is the correct phrase here.
I rather believe Mr. Stewart's interest in aviation,and movies, allowed him to put both together in so many films, and with great success.
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you may want to consider the wording of your post,I may be missing your point...
I'm with you, Thorsail. Jimmy Stewart was very comfortable around aviation. Another of his great films, "Strategic Air Command" is beyond a classic. I would guess that in this earlier roll, his knowledge and experience would have given him many things to draw from in creating the character of Prof. Honey.
The certainly don't make them like him, or this movie, anymore.
If I had a dollar for every time I got distracted...Oh, look!! A puppy!!