Originally Posted by
Arrivals
You call the call center and tell them you've got one of those letters. Then they ask you about the original booking code. They verify the delay and the class and you can (immediately) book a new flight in Y (or C, if the delayed flight was in C). You have to pay the taxes, no 20 € booking fee for calling, no miles for the flight though. The letter also excludes most of the interesting dates - not during summer, easter, christmas.
On domestic flights you can ask for the letter if you have had a delay of at least one hour.
Thanks. I may try to use this one I've got but it's only for domestic so hardly worth it. I do wonder if a specific fare bucket (i.e. the cheapest) has to be available or if one of these free booking can be had at short notice in the higher classes when it's more worthwhile. I will post about my experience if I ever book anything.