Best/Most Direct Airline to fly Wash DC to Athens

I'm going to suggest that you try searching on kayak.com which will let you filter by number of stops and connecting city and sort by flight duration. There are no non-stops to Athens out of DC.

Generally, I prefer to fly out of Dulles and when a connection is involved, I prefer to transfer in Europe. I generally choose based on a combination of price and route. I've found AMS, ZUR, and MUC to be good airports for transfers. I avoid connections at CDG. While FRA and LHR are not my favorites, I've probably connected through these cities more than any others as there are so many flights to these cities and there are also late afternoon flight out of these cities back to DC. That means you don't have to leave at the crack of dawn to make a connection when returning home.

See what your options are on kayak and then come back and we can help you narrow it down.

I would consider Turkish Airlines which flies directly from Dulles to Istanbul overnight and you'll have a short transfer afterward. A lot of Turkish Air flights have long or overnight layovers but the prices are unbeatable (less than $800 round trip) - not sure about Athens, you'll have to check. It's too early to book - I would say start tracking prices around 6 months in advance (and tracking them over a number of months) and then jumping on a good fare once you see it.

PS. [Edit] I flew Turkish Air to visit Malta this September - that's how much I like Turkish Air. I did have a an extra day in Istanbul both ways and really enjoyed it (I've spent time there before so it was like visiting an old friend). Even with the Istanbul hotel rooms added on and the 20 Euro Visa to leave the airport, I still managed to pay less than other airlines because the flight fare was $760 or so. The food and service on board was really great and I would definitely fly them again.

I replied on your other thread, but I'll add to Agnes' reply. Turkish Air is not only often cheaper than other carriers, but nicer. The food is actually good, the flight attendants are pleasant, there's a modicum of legroom - it's been said that Turkish Air is old fashioned, in a good way. No joke, it really is nice, and for Athens, it won't be as much of a detour to go through Istanbul as it is for western European destinations.

Since there are no nonstops to Athens from DC, I'd definitely try to fly Turkish, unless it was significantly longer than other options.