Rosamunde Pilcher a British writer not that well known in her own country wrote numerous novels, some set in Cornwall. German tv filmed them using locations in Cornwall and they became phenomenally popular in Germany leading to what is almost a cult that attracts German visitors to the county year after year. Cornwall had been popular with German visitors for many years before the Pilcher effect anyway. I don't think a Stuttgart route is likely, with Eurowings or anyone else. Most of the major German airports are covered from BRS one way or another.