A planned strike by Greek air traffic controllers is set to disrupt flights to and from the country today (Tuesday).
The walk out is being staged for four hours from midday local time.
EasyJet has been forced to change the departure times of a number of flights as a result.
The budget carrier urged passengers flying to any destination today to check the status of their flight on its website.
Olympic Airways has cancelled 10 flights and re-scheduled 22 others.
The industrial action is part of a wider 24-strike in Greece in protest against austerity measures.
The metro link from Athens airport to the Greek capital iand other public transport is also likely to be affected although ferries are expected to run on schedule.