Can an elderly person with fractured ribs fly in an airplane?

Potentially: There is a theoretical concern about any associated pneumothorax and rib fractures and any potential changes in cabin pressure, also pain would have to be under good control. So if she was comfortable, had happened over a couple of weeks ago, and had an X-ray showing no pneumothorax, it would be reasonably safe. Particularly with planes now in which cabin pressure is so well maintained.

Flying w broken ribs: IF the injury which caused the rib fracture was carefully evaluated (chest film, other studies, careful exam) and there is no difficulty breathing--maybe. Rib fractures can allow air into the sac which covers the lungs which can expand and impair breathing. Rib fractures may be quite painful, especially if multiple, and lead to breathing impairment, especially with underlying lung conditions.