Defining the first naval aviator to command a carrier

Who was the first Royal Navy aircraft carrier commander who was also a naval aviator?

It depends on whether observers and escort carriers count; for a pilot commanding a fleet carrier, Caspar John is a likely answer, with qualifications.

The definition determines who qualifies. Observers reached escort-carrier commands early, while a fleet-carrier command by a pilot may point toward Caspar John, with Charles Lamb also entering the discussion. Many Royal Navy officers acquired aviation experience outside the narrow pilot-training route because interwar Air Ministry control limited formal places.