A German Luftwaffe Staffelkapitän with the rank of Oberleutnant in front of a Junkers Ju 88A bomber during the Balkan campaign, spring 1941. Staffelkapitän is a position (not a rank) in flying units (Staffel) of the German Luftwaffe that is the equivalent of RAF/USAF Squadron Commander. Usually today a Staffelkapitän is of Oberstleutnant or Major rank. In the Luftwaffe of the Wehrmacht the Staffelkapitän usually held the rank of an Oberleutnant or Hauptmann. For the first weeks of his assignment he was known as a Staffelführer (Squadron Leader), until he was confirmed in this position. If a Non-commissioned officer was tasked with this role, he was also referred to as a Staffelführer. With the beginning of the Balkan Campaign, yellow fuselage bands were introduced for those Luftwaffe units involved. Yellow wingtips, especially lower wings and rudders, were used additionally. Completely yellow painted engine cowlings disappeared with fall of 1941. Apart from these theatre, refered markings staffel or unit leaders always preferred yellow or white painted rudders. The colourful wing and rudder markings gradually disappeared towards the later war, when allied air superiority made more camouflage efforts necessary.
Book "The Second World War in Colour: Luftwaffe" by John Christopher