Flights were grounded for several hours in Greece yesterday as air traffic controllers joined a general strike over new austerity measures.
All international and domestic flights faced disruption for four hours from 11am while other transport methods also faced a shutdown.
All passenger ferries across Greece are likely to remain in port due to two 48-hour strikes which have been timed to run until the end of the week, the Foreign and Commonwealth Office warned.
A further 48-hour strike for May 18 and May 19 was also arranged, according to the UK Foreign Office.
At least eight Olympic Air flights to and from Athens were cancelled on Wednesday and 100 Aegean and Olympic Air services re-scheduled.
Thousands of people stopped work yesterday and marched through Athens to demonstrate over the measures being demanded by international lenders.
Meanwhile, the cleaning company for the terminal buildings at Ibiza airport announced a strike from yesterday.
EasyJet said: “Please be aware that during this time the terminal and facilities in the building may not be cleaned.
“We therefore recommend using our facilities on-board our aircraft or before travelling to the airport.”