For those deciding at the last minute, note that Aegean is offering a flash sale valid for 48 hours on all international flights to or from Greece between July 1 and October 31.
https://en.aegeanair.com/flight-deals/offers-competitions/greece-international-offer/
The promo ends on 20 June at 23:59 Greek time.
I have no business relationship with Aegean apart from receiving its offers, it's just for information