Delta/KLM have Chicago to Athens as low as $552 round trip for departures in October and $571 for travel in August and September. There are low fares under $600 round trip available through March 2017. Some of the low fares for August travel are available through OTA sites where Google Flights shows no online booking availability through Delta of KLM. Momondo.com meta-search for an online ticket through an online travel agency offers a good alternative to making a phone reservation with $25 fee with the airline.
Delta/KLM Chicago ORD – New York JFK – Athens ATH – Amsterdam AMS – Chicago ORD
$570.34 round trip Wed Aug 17 – Thu Aug 25 SmartFares.com
This fare has an overnight layover in Amsterdam on the return flights.
OTA smartfares.com fare found through Momondo.com.
Delta Airlines Chicago ORD – New York JFK – Athens ATH – New York JFK – Chicago ORD
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