I can't comment on the piloting bit but since your wife is German and you live in Germany, do you think you could apply for a German passport? Section 12 of the Nationality Act in Germany states that generally, you must renounce your previous citizenship to be naturalised in Germany (they don't like dual-citizenship for outsiders it seems), however it's worth seeking professional advice in case there are any other routes. Since Kiwis are part of the British Commonwealth, maybe you can get some kind of visa for the UK if that interests you otherwise?