[Shiner]

Ahoy:
I recently came across a book entitled Rank & Rate (Royal Navy Officer's Insignia Since 1856) by E.C. Coleman published by The Crowood Press 2009, ISBN 978 1 84797 138 8.
Chock-a-block with photos, colour illustrations and detail regarding various branches including info on the RNAS. If I may quote segments:
"Between 1912 and 1914 Royal Navy aviation consisted of the Naval Wing of the Royal Flying Corps... On 1 July, 1914 (this unsatisfactory arrangement) came to an end) when the Naval Wing was placed completely under admiralty control as the Royal Navy Air Service." The author continues with very detailed information on the introduction of the eagle above the executive curl on the sleeve rank.
With respect to the cap badge, he continues in a separate chapter that:
"Officers of the RNAS were considered to be a part of the Royal Navy Military Branch... officers transferring to the RNAS continued to wear the RN cap badge, officers who directly entered the RNAS wore the RNAS eagle in place of the anchor."
I hope that helps.
I have attached a metal cap badge from the Armoured Car Division to elaborate on the expanse of the RNAS. I tried to attach a photo of the vehicle depicted in the badge, but to no avail. Additionally, I had the misfortune of coming across a repro of this badge that lacked certain details shown in the original. I shall add that to the rogues gallery at a later time.
I hope this helps cast some light on the subject. great collection of hats, by the way.
Shiner