Most pilots seem to agree that stiff collars and ties were ditched, in favour (if possible) of a silk scarf, to lessen the onset of “fighter pilot’s neck,” or soreness caused by continually swivelling the head to look behind. A mirror wasn’t (officially) fitted to the Spitfire until September 1940, although it seems that pilots tended to raid local car showrooms. Some pilots, whose flying dated from before the war, still flew in the original 1930s-vintage white overalls.
Edgar