Interesting question, Treadders, and one which — in many years of researching, writing and reading about Austers — I have never seen answered or even thought to ask. If the dictionary definition as quoted by Wub is the only one, it is bizarre indeed, and the only Auster name that doesn't make at least some sense in an aeronautical/role context. Since Auster has a Roman root, I wonder of Aiglet might, too? My classical education, such as it was, is too far back for me to recall. Or maybe it's 'Eaglet' in Leicestershire dialect!
BTW: not forgotten your Stampe, presently buried under heaps of stuff in the loft.