This is a doctor whose job is to accompany patients being repatriated if they're ill or injured abroad, or otherwise fly them somewhere else for treatment, or to organise this service. You could just say 'medical escort', or add 'physician' to make it clear they're not a nurse.

Médecin régulateur dans l'assistance : les globe-totters de l'urgence
Leur mission : organiser et accompagner la prise en charge médicale ou le rapatriement sanitaire des clients de la compagnie d'assistance qui les emploie.
http://www.tourmag.com/Medecin-regulateur-dans-l-assistance-...

A medical escort is a non-emergency medical service provided by commercial aircraft, by medical escort companies, and sometimes by self-employed medical escort freelancers, who typically work for a medical repatriation company... Medical escort physicians consult with the referring physicians to jointly determine the most appropriate level of care and most suitable method of transportation.
en.m.wikipedia.org/wiki/Medical_escort

It's possible that 'compagnie' means 'airline' - this may be apparent from the wider context.