Travellers face the prospect of strike action by easyJet pilots based in Lisbon over the Christmas and new year holiday period.
The Foreign and Commonwealth Office altered its travel advice to Portgual yesterday as a result.
The FCO advised people flying to and from the Portuguese capital with easyJet to contact the airline or their travel company.
The airline faces possible strike action by Lisbon-based pilots which may affect flights on December 24, 26, 31 and January 1.