After strikes caused disruption during the February school holidays, more industrial action is planned by transport workers in the run-up to Easter.
Travellers could face disruption in Spain, France and the UK between now and the busy holiday period.
Read on to find out where and when are walkouts taking place.
If your flight or train is cancelled or delayed, you will be entitled to a new ticket or compensation. Read our guide for full details.
German transport unions call for widespread walkouts
Unions Ver.di and EVG have called for thousands of transport workers across Germany to walk out for 24 hours on Monday 27 March. They are striking for wage increases that are in line with high rates of inflation.
Members of the Ver.di union include security and ground workers at all German airports except Berlin, local transit workers in 16 of the country's states, harbour staff and highway workers.
Frankfurt Airport has already warned of "massive disruption" on Monday, saying that operations will be "heavily disrupted" throughout the day. Munich Airport announced that there would be no passenger flights on Sunday or Monday.
EVG has called on 230,000 staff at Germany's main government-owned railway operator, Deutsche Bahn and other companies to walk out.
No long-distance trains will be running either and regional rail services are also likely to be cancelled too.
"This will affect all German rail operations, as employees from all areas of Deutsche Bahn and other rail companies have been called on to walk out," the rail operator said in a statement.
"The long-distance traffic of Deutsche Bahn is therefore completely discontinued."
Passengers with trips planned on Monday are being urged to reschedule for the next day. Those travelling on Sunday have been warned to "be at their destination in a timely manner" as evening services could also be affected.
Strikes at 17 Spanish airports
Some of Spain’s busiest airports are facing strikes by unionised workers at ground services and cargo handling company Swissport between now and Easter.
From 27 February to 13 April, they have called for a series of 24-hour walkouts every Monday, Tuesday and Thursday.
Swissport Handling provides services at Madrid-Barajas, Barcelona-El Prat, Reus, Alicante, Valencia, Murcia, Málaga, Almería, Salamanca, Valladolid, Burgos, Logroño, Zaragoza, Huesca, Lanzarote, Gran Canaria and Tenerife Sur airports.
Unions will have to provide minimum services, as is required by Spanish law, so it isn’t yet clear what impact the strikes will have on passengers.
Travellers warned about French pension protests
Unions across France have been in an ongoing battle against plans to increase the legal retirement age from 62 to 64.
Protests have broken out across the country after President Emmanuel Macron decided to push the change without a parliamentary vote. Rubbish has built up in Paris and was set on fire. Protesters have also clashed with police in the French capital.
Travellers haven't been advised to avoid France but the UK Foreign Office has urged people to keep an eye on media reports and check the latest advice from operators to avoid demonstrations.
"If demonstrations do turn violent, a heavy police/gendarmerie presence is to be expected. In all cases, you should avoid demonstrations wherever possible and follow the advice of the local authorities," it said in a statement.
In particular, tourists are advised to avoid the Place de la Concorde, located between the Champs-Élysées and the Jardin des Tuileries, the National Assembly and the eighth arrondissement as these are assembly points for protests.
Heathrow strike: Disruption likely during Easter holidays
1,400 security guards at London’s Heathrow Airport are going on strike over the Easter holidays.
The guards who work in Terminal 5, the main portal for British Airways and where many international flights depart and arrive, will be walking out for 10 days from 31 March until 9 April.
They are striking over low pay, after rejecting the airport's offer of a 10 per cent pay increase. Unite union secretary general Sharon Graham says Heathrow workers are on "poverty wages while the chief executive and senior managers enjoy huge salaries." A security guard at Heathrow is paid as little as £24,000 (€27,400) a year, according to the union.
The union says the “strike action will cause huge disruption and delays at Heathrow throughout Easter.” But Heathrow says contingency plans will be in place to ensure the airport stays open, saying it will be "open and operational despite unnecessary threats of strike action by Unite".
When are UK passport workers on strike?
Although this strike doesn't affect any transport services, it could stop you from taking a trip.
More than 1,000 members of the Public and Commercial Services union (PCS) working in Passport Offices in England, Scotland and Wales are to walk out from 3 April until 5 May.
The strike will involve those working in Durham, Glasgow, Liverpool, London, Newport, Peterborough and Southport.
The Business Travel Association estimated that more than one million passport applications are due to be processed during the strike period.
Italy airport workers to take part in a nationwide strike
Italy’s ENAV air traffic controllers will strike from 1pm to 5pm on 2 April. This will be nationwide.
For more information about the likely impacts, check the ENAV website closer to the date.
If you know of a big strike happening in your country that we have missed, we'd love to hear from you via Twitter.