What earlier Royal Navy control could have changed

Would the Fleet Air Arm have been better positioned if the Royal Navy regained control in the early 1930s?

Yes. Earlier control could have enabled a complete pre-war procurement and engine-development cycle, potentially producing stronger aircraft by 1939.

Regaining control in the early 1930s would have allowed the Royal Navy to define requirements and order equipment years earlier. Reginald Henderson's 1933 appointment provides the starting point for a full six-year development cycle before 1939. That interval could have delivered engines of at least 1,000 horsepower and perhaps more ambitious 1,200- to 1,400-horsepower units. The result is a plausible opportunity rather than a guarantee of perfect aircraft.