This is an annoying bug that could be fixed. If I enter a destination and Navigator doesn't find a route it will start a navigation anyways. After stopping that navigation Navigator is out of order and needs to be killed.
The reason to start anyway is that it could be caused by temporarily wrong GPS position or single unconnected link. Can you try latest 1.2.50+ from http://download.mapfactor.com/mapfactor_navigator.apk which contains many bugfixes?
The flughafen Kindel is not in Kindle it is in Hörselberg-Hainich. If you enter flugplatz str it will find a route, however the streets around the flughafen (am flughafen) are not named in OSM so unless you pick the street from the map you wont find it in a search. Also some of the streets are not connected. Only way to fix this is to become a member of OSM and edit the maps. I tried to replicate your problem and chose the flughafen as a destination by picking it from the map display. I did get a route not found (there are no streets connected to this short stretch), but navigation did not start so was unable to reproduce your problem.