My first wife's late father was involved in one of those "Urban Myths" during WW2.
He was involved with building the extension to the airfield at Gibraltar and was offered a quick flight in an RAF 2 seater plane. Once airbourne the pilot was taken ill and my late father-in-law had to land it himself on his first air trip.
He was later involved with something to do with the escape route through Spain. The only part that I heard was that he was disguised as a "Don" (not quite sure exactly what he meant by that), but the local priest suddenly wished him well in English, so the disguose was not perfect!
He would never visit Spain again after the war because fear of some sort of retribution, real or imagined.