Not if there is an agreement between national pilot unions not to break any strikes within the company....
But then there have to be unions, and agreements...
And how, pray tell, does that work?
In the UK you can only strike when it is your own terms and conditions affected. You can't go out on a sympathy strike and if you do you have absolutely no protection and will probably be fired. As has been said, it was only UK crews used, flying UK based aircraft which bypassed Portuguese laws about strike breaking. No doubt they were used as the UK labour laws are far weaker than the other countries where easyJet has bases.