I have a 8:00 AM flight with British Airways. When do I need to arrive at airport?
What does BA say/recommend?
Personally I would be there no later than 6AM.
I'm not sure what you are asking. Are you talking about what time to get to the airport you are departing from to get to Athens?
If so, then 2 hours would be recommended to ensure time for checking in and going through security.
It all depends on what country you are flying from and the size of the airport, etc.