Yeap. All the tests with volunteer "passengers" are almost finished and some test flights have also been made. However, I think there is a problem with the navigation systems not being set up yet. And Lufthansa have cancelled their test landing due for tomorrow because they said that 'the airport doesn't have a licence yet'.
The basic delay is the motorway to Athens (Attiki Odos), which is not ready. They only need to supply a 20km strip connecting the new airport to the northwestern suburbs of Athens. However, the schedule is very tight, so, even though the construction company has promised that the motorway is going to be ready before March, nobody wants the airport to open without a proper connection to the city, so they are hesitant to give a precise opening day of the airport. They only say that it is going to be a Wednesday, I don't know why (it could be the day with the less traffic, I suppose).
Initially, the airport was to open on the 1st of March. Now, the Minister for the Environment, Planning and Public Works says it's going to open 'SOMETIME in March'. I believe that it's going to open sometime in March, even on the 28th of March. The political cost for the government would be huge if they delayed this so much advertised airport.
I hope that they open it soon. The current airport (Hellinikon) is a total disgrace for the whole tourism industry. No repair works are being done at all, since the employees there say that 'we're moving in a month or so, so why bother?'. Someone has told me that they don't even bother to change the broken lights of the runway.
I have a flight via ATH going to SKG on the 24th of March and I return on the 17th of April. I hope to visit the new airport at least once!