Just to add to the debate about nationalities on flights based on my experience . City/business destinations can be very mixed between Brits and locals. BIO is often heavily skewed towards Spanish and SKG in the winter is predominantly Greek. KEF sees a lot of Icelandic’s heading to Manchester (for some City culture/life no doubt given where they live) There can be a large number of non-EU nationals on most city/business routes too. Lots of Chinese, Australians, Canadians and Americans. Indeed, my carrier has an American website.
Holiday destinations, unsurprisingly, tend the be mainly Brits of course but places like PFO can see a large number of Cypriot students at various times of the year. Some of the more upmarket Greek destinations such as JTR and JMK can also see a number of non-Eu nationals too.
TLV is of course a massive VFR Route from both ends of the route.