Both Aegean Airlines and Olympic airlines are asking their customers to call to reschedule their flights, but this affects all airlines flying into, from, or around Greece, many of which are listed here.
Some Useful Contact Numbers:
Olympic Airlines (in New York) 1-800-223-1226
Olympic Airlines (in Greece, from the US) 011-30-210-966-6666
Aegean Airlines (in Greece) 801-112-0000.
Aegean Airlines (in Greece, from the US) 011-30-210-626-1700
Obviously, this strike will make flying in Greece a challenge both before and after the strike as planes have to be shuffled around and airlines are forced to handle a higher volume of passengers than usual. Expect possible delays for the next several days.