I wanted to report some limitations on the pass usage with 0-day booking window. The limitations probably come from the way Aegean handles all flexible tickets, but these were not clear to me when purchasing the pass. I am also yet to find the limitations spelled out anywhere.

I was trying to perform a same-day domestic flight change. Any departure within 1 hour from current time seemed to be selectable/bookable through the flight modification process. However, when proceeding with a change to a flight departing in 2 hours, I have received an error of "You have to make your reservation at least 3 hours prior to your departure time". It took me some time to reach the call centre, and they agreed to make the change but requested 20 Euro handling fee. Feeling piqued by the unexpected charge, I declined.

To my surprise, a bit later I did succeed to change the flight at Thessaloniki airport at the Aegean ticket sales counter; for free. Even though it was only 57 minutes before the departure time.