The ordinary 90-minute Athens ticket is €1.20, and it explicitly excludes the metro section from Koropi to the airport and the airport express buses. The €4.10 24-hour ticket and the €8.20 five-day ticket exclude them too. Only the €9 airport ticket, the €5.50 express bus ticket and the €20 three-day tourist ticket will get you out.
The Ministry of Infrastructure and Transport raised the fixed Athens airport fare from €40 to €50 by day and from €55 to €65 overnight. The airport's own private-transport page still publishes the old €40/€55, and so does every guide online, which means a driver quoting €50 looks like a cheat when he is simply correct.
The fixed price covers the Attiki Odos motorway tolls, all bags, the airport pickup fee and VAT. There are no legitimate extras, so a demand for a suitcase charge, a toll supplement or a night surcharge inside the flat-fare window is an overcharge.
The €5.50 airport express ticket is valid for a single trip from or to the airport. It is not valid for onward transfers onto the metro or city buses, and it is not valid on the X80 line — unlike the €9 metro airport ticket, which does include 90 minutes of onward travel.
Men offering a taxi inside the terminal are not the rank: the official rank is at Exit 3 of the Arrivals level, and only yellow licensed taxis may use it. The price quoted inside is always above the regulated fare.