EasyJet has been forced to rearrange flights as air traffic controllers in Greece are planning a four-hour strike from midday.
The airline urged passengers to check the status of their flight via the easyJet Flight Tracker Live Updates.
It said a number of departure times had been changed.
A message said: "Whilst this is outside of our control we apologise for the inconvenience caused, we will update you with any changes on the day via our Flight Tracker."
A spokesman for British Airways said it plans to operate a normal schedule to Greece.
A Ryanair spokeswoman said: "We don’t envisage any cancellations and delays as a result of the strikes tomorrow."
EasyJet has also warned of strike action by security staff at Basel airport in Switzerland.
The airline advises that lengthy queues are likely to get through security and to improve the situation, it will be opening the baggage drop facility three hours before departure time.
