Goofs

When Brad takes Carol flying, at least two different aircraft are used (differences in struts, undercarriage, etc).

In the final test-flight, at the peak of the power dive, the pilot's scarf (and probably the observer's too) is seen to be tied back at full-stretch by a piece of string to make it look as though the airstream is strong.

For ground scenes when Brad takes Carol flying, the aircraft cabin has most of its glazing removed to avoid reflections.