Holidaymakers heading to Portugal next month could face major travel disruption as cabin crew, rail workers, and public transport staff prepare to walk out in a nationwide strike. With hundreds of flights potentially affected and Lisbon already battling long airport queues, travellers are being warned to brace for delays at the start of the busy summer season.The strike will take place on 3 June and, according to Portuguese newspaper The Resident, the number of flights set to be affected could be as high as 500.  The move comes after members of the Portuguese cabin crew union voted to join the nationwide strike, which will also see doctors down tools. TAP, the country’s flag carrier, may see up to 300 of its daily flights affected, and other airlines, including Portugália and SATA, may also be hit.Cabin crew and other strikers are protesting reform proposals from the government, with the National Union of Civil Aviation Flight Personnel (SNPVAC) calling the ‌proposed ⁠changes an “unprecedented attack on established rights”.The government’s planned reforms would make it easier for companies to sack workers and loosen restrictions on outsourcing.Reports indicate that some 79% of the cabin crew union members voted to join the national strike. It’s not just flights that will be impacted. FECTRANS, another trade union that represents public transport, will also take part.That means the likes of the Lisbon Metro and public transport across the country will be impacted, causing issues to residents and visitors alike. The disruption will come at a time when the controversial EU Entry/Exit System (EES) is causing problems for travellers. Travellers have already been warned to prepare for serious disruption, including hours-long queues, across European airports this summer, as the rollout continues. Tourists have already faced long queues at Schengen area airports, and the hub in the Portuguese capital of Lisbon has been toggling the EES system on and off in an effort to ease congestion.