Anti-austerity strikes across Europe have brought disruption to UK airlines and rail services.
British Airways and easyJet were among UK carriers forced to axe some flights.
In Belgium, one of the countries where workers joined in the day of action, high-speed Channel Tunnel train company Eurostar had to cancel one of its London-Brussels services.
Flights to and from Spain and Portugal were the worst hit by the strike, which was also called to protest against the continent's unemployment levels. Among the 200 Portuguese flights that had to be cancelled were some operated between London and Lisbon by British Airways.
BA also had to axe eight round-trip flights between London and Madrid and Barcelona.
Portuguese carrier TAP's cancellations included some London to Lisbon and Porto services, one Lisbon-Manchester flight and one Heathrow to Funchal in Madeira service.
Some Ryanair flights between Europe and the UK were delayed, with a flight from Limoges in France to Stansted four hours late. Monarch Airlines axed one Gatwick-Funchal service and one Funchal-Gatwick service.
EasyJet cancelled some UK-Spanish services as well as more than 20 within-Europe flights. Some other easyJet flights were badly delayed - with a London service to Thessalonaki in Greece delayed for three hours and 40 minutes.
Heathrow said that of its normal 1,300 daily services, 39 flights - nearly all involving Spain or Portugal - had been cancelled. The west London airport said its terminals had not been overly crowded as most people learned of the cancellations in good time.
The Eurostar service that had to be cancelled was the 10.57am from London to Brussels, with affected passengers being accommodated on a later train. Those arriving in Belgium found local train services axed. Ferry sailings to and from the UK were unaffected, while Eurotunnel's Channel Tunnel services operated normally.