I just wanted to send a warning to those who are thinking about flying Olympic Air to be careful. I had bought 4 tickets roundtrip with them for Athens->Santorini (May 13 and May 18) and my flight out of Santorini was just changed from 7:10 AM to 10:30 AM, which is problematic since two people in my group has to catch a Delta flight at 11:30 AM back to the US. My own tickets to Rome was changed from 9:05 AM to 1:30 AM as well. Of course, they are willing to refund the tickets, but this sucks since I will have to rebook on Aegean and their tickets are more expensive now since the sale is over for my flight dates. :(
Olympic seems unreliable so if you are booking with them, please give yourself some buffer in case crap like this happens.