What is "commodore-in-chief"

Commodore-in-chief is an honorary appointment bestowed by the monarch of the Commonwealth realms on various members of the Royal Family. Previously, there have been honorary air commodores-in-chief in the British Royal Air Force and Royal Canadian Air Force, but no parallel affiliations with the navies of either country.

Commodore-in-Chief is an appointment rather than a rank. Holding an appointment of commodore-in-chief does not confer upon the holder the rank of commodore or indeed any other rank. Members of the Royal Family wear the uniform of their rank and are not issued with a different uniform for the appointment.