Since you brought up this topic, anyone needing plane transportation for doctor's visits might also try contacting the corporate angel network--which uses corporate jets during downtimes to give rides to cancer patients. I didn't use them but was told by a fellow breast cancer survivor I could get a flight with limo at the other end to New York to visit Sloan Kettering through a corporation near here (it's a 4.5 hour drive to NYC from here).

Their website:
http://www.corpangelnetwork.org/

Nelie