I'm Italian living in Spain. I have an NIE. My wife (she is Argentinean) came here and we tried to get her NIE (she gets a "permiso de residencia de familiar de ciudadano de la UE" which is a permission because she is an EU citizen's relative) but one document was missing. Now we have presented that document but the NIE process is not over yet. Her 90-day visa as an Argentinean has expired and we have flight tickets to Berlin, Germany on December 22.
Most probably the NIE will still be in process on that date, so is it safe to do the travel or should we cancel it?