Can i just ask one thing, why DO you call them Crab Air?!
'Blue Unction' was another term for it.Crab, crabfat - (RN) A member of the Royal Air Force. From the light blue color of the uniform, which is the same as that of the grease (known as ‘crabfat’) used on gun breeches, etc., in the RN. Accounts vary, but apparently the grease was called ‘crabfat’ because it resembled in color the ointment used to treat sailors for ‘crabs’ (pediculosis pubis, genital lice), and of which fat was a major constituent.
From [btinternet.com/~a.c.walton/navy/smn-faq/slang1.htm] link no longer exists
When trenchard was consolidating his RAF after ww1 funds were very tightThe original dye colour for their uniforms, back when they formed, was the same colour as medication used by the Navy against crabs. The uniforms were originally destined for Russia I believe, but the revolution put paid to that, so the RAF got them on the cheap.