The website is having some major issues for sure. Was able to do a few checks for prices just around midnight, but now most queries result in an error. I did notice that Flex and Comfort are discounted pretty good. On a KLX-ATH-SKG-BRU (crazy) itinerary I'm interested in it was showing 6 euro to go from Light to Flex, and 10 euro to go from Flex to Comfort. Just that 10 euro from Flex to Comfort adds 1000 status miles, making it well worth it.

You can use Google flights to find fares while the Aegean website is having issues, but - only Economy Light and Business basic are shown there. And you cant actually book that way