Who controlled carrier aviation in 1927?

Were the carrier aircraft naval or RAF at this point?

They were formally RAF-controlled, but the Fleet Air Arm included naval officers who could also hold RAF flying rank.

The Royal Naval Air Service disappeared as an independent organization in 1918, yet aviation operating with the fleet continued to be called the Fleet Air Arm. Formal control lay with the Royal Air Force during the 1927 Bias Bay operation. A negotiated arrangement nevertheless placed naval officers among its personnel. Those officers could hold both naval rank and an RAF flying rank. The result was a hybrid command and career structure behind operations from Hermes and Argus, rather than a clean division between naval ships and purely RAF airmen.