Just 2 points to make:
1, easyJet Switzerland operate oputside the EU
2, Stelios in a European Citizen so even if he did owner all of EZY (which as rightly pointed out he doesn't) then he would still have the right to fly from the UK to outside the EU, ownership just has to be within the EU not the country of domicile (look at BY/BLX/JMC etc all owned within the EU not the UK)