Originally Posted by
WillTravel
On rare occasions, a flight that's meant to be EU-EU or Schengen-Schengen may have to land in a non-EU or non-Schengen country for emergency reasons. So even if you are entitled not to, I'd still want a passport in this case.
Hm, this would be very very VERY rare. Former Yugoslavia - you'd most likely be fine with an ID, even in Serbia. Morocco on the way to/from the Canaries - probably OK too with just an ID. Turkey to/from Cyprus - you'd be fine. The only scenario I can think of is like Cyprus to the Baltics/Finnland, with a landing in Lukashenko-Belarus (Ukraine would be fine, though).