Massive anti-austerity strikes across much of Europe are causing headaches for travelers, sparking hundreds of flight cancellations and train disruptions.

British Airways and Easyjet have scrapped or rescheduled flights from London to Madrid, Barcelona, Lisbon and Thessalonaki, Greece because of Wednesday's general strike organized by the European Trade Union, reports AFP. Flights from southern Europe to Paris' Charles de Gaulle and Amsterdam Schiphol also were canceled.

Eurostar's train services have been affected, with the company warning that "further disruptions are possible throughout the day and customers are advised not to travel."

In Spain, just 20% of the country's long-distance trains and a third of its commuter trains were running, and in Lisbon, the Metro was completely shut and only 10% of all trains are expected to run, says London's Telegraph.