EasyJet has cancelled 26 flights today and rescheduled 10 in the face of a Europe-wide general strike.
Flights have been dropped from Gatwick to Madrid and Barcelona while others to Athens from Gatwick and Manchester and Thessaloniki from Gatwick are among those that have been re-scheduled.
British Airways warned of disruption in countries such as Portugal, Italy, France and Greece and advised passengers due to travel to check the status of flights before setting off.
Some 40 groups from 23 countries are involved in today’s Day of Action and Solidarity in protest against austerity measures.
The Foreign & Commonwealth Office cautioned that public transport within Spain and services at Spanish airports are likely to be “significantly disrupted” and public demonstrations in city centres may also affect local services today and tomorrow.
In Italy, the strike will affect flights between 10am and 2pm and national rail travel between 2pm and 6pm. Ports will also be affected, according to the FCO.
EasyJet said it had been advised of a general strike today organised by the European Trade Union Confederation, with strikes and demonstrations across Europe.
“This will affect different countries at various times. Spain and the Canary Islands will be in a 24 hour strike period from 00:01 to 23:59 and Greece will be in a strike period from 12:00 to 15:00.
“We continue to monitor the Portuguese situation, however at this time we have not made any amendments to our flying programme through Portugal. ”
The budget carrier said it was” proactively trying to minimise disruption” but warned passengers that they could face delays, cancellations or flights being rescheduled.
The situation in Spain is compounded by an ongoing baggage handlers strike at Madrid airport.
Monarch Airlines said it planned to operate all flights as scheduled today during the industrial action in Spain and Portugal.