It was also on Turner Classic Movies last weekend.
In the lead-in introduction, Ben Mankiewitz mentioned that one of the male leads actually had been a combat pilot in the Great War, and the other male lead had never been in an airplane, and was taught by the first guy, so all the aerial shots are actually them flying.
Another point of interest for me was that it was filmed in the area that later became Randolph Field, 'The West Pont of the Air.' My junior high homeroom teacher, Mrs. Cornelia Randolph, was Lt. Randolph's widow.