Here is a link to information about the RAF tartan.
http://www.kamrafa.co.uk/
My late father served in the RAF from 1940 to 1946; he was based in Canada with 36 SFTS at Gananoque, Ontario and Penhold, Alberta, from 1941 to 1943 and then with 57MU on the Solway coast, hence my involvement with the Solway Aviation Museum. My RAF kilt is pleated to the sett and is worn in honour of my late father; for servicemen and ex-servicemen they are normally pleated to the stripe.