Royal Naval Air Service other ranks 1914 - March 1918:
The National Archives
DocumentsOnline
For a fee of £3.50 you can view digital copies of service records up to 1918 in DocumentsOnline
The Catalogue
Information relating to the service until 1918 (when the Royal Naval Air Service and Royal Flying Corps were amalgamated to form the Royal Air Force) can be found in series ADM 188.