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.
Where and when are walkouts taking place?
German airport worker strikes
On 27 February, airport security staff will walk out over pay at two major German airports: Cologne-Bonn and Dusseldorf.
Strikes at Cologne-Bonn will commence in the evening of 26 February and continue into Monday evening. All but two of Monday's 136 planned flights are expected to go ahead, German news agency dpa reports.
In Dusseldorf, only 89 of the planned 330 flights are expected to take place as scheduled, with most of the rest being cancelled.
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.
Ongoing pension strikes in France
Unions across France have been in an ongoing battle against plans to increase the legal retirement age from 62 to 64.
The industrial action has previously included railway workers and airport staff with 30 per cent of flights from Paris’s Orly airport cancelled on the last day of strikes.
On 7 March, unions are planning the biggest day of action yet and are promising to bring France to a complete standstill.
After that, they are debating whether to switch to rolling strikes; Paris Metro workers are one group in favour of swapping to industrial action that can start and finish any time during a specific time period.
Heathrow workers vote on Easter strike action
More than 3,000 security guards, engineers and firefighters who work at Heathrow Airport are currently voting on whether to strike over low pay.
If the workers, who are members of the Unite union, vote in favour of the industrial action, it could coincide with the busy Easter holiday period.
“If our members at HAL (Heathrow Airport) take strike action it will inevitably cause severe disruption throughout Heathrow with delays, disruption and cancellations of flights inevitable,” says Unite regional co-ordinating officer Wayne King.
UK Border Force workers continue to strike
A series of targeted strikes is being organised by the Public and Commercial Services union in the UK. This includes Border Force staff who will be taking part in a day of mass action where 100,000 civil service workers plan to walk out on 15 March.
The walkout will coincide with the government’s Spring Budget and could affect airports and sea ports across the country.