Great pictures, Ash.
Aviador has pointed out the popularity of Yugoslavia (or Jugoslavia which was often the spelling when I was at school in the 1950s) due in no small part to the relative cheapness of the holidays.
Of course Yugoslavia then included the likes of Croatia, Slovenia, Montenegro, Bosnia & Herzegovina, Macedonia and Serbia which presented an incredible variation of landscapes and holiday venues: as well as the hugely popular beach holidays there were lakes and mountains holidays in Slovenia to rival Austria; others enjoyed visiting the ancient cities and other historical sites.
Everything came to a juddering halt in the 1990s with the conflicts although in recent years some of the countries that made up Yugoslavia are becoming extremely popular again for UK and other European holidaymakers.
Back to you pics, Ash, which bring back memories of up to 30 years ago with Inex-Adria, JAT and Aviogenex, all or some of which visited every UK regional or local airport worthy of the name in those days.
To digress, I enjoyed seeing the Spanish airline Aviaco DC9 in one of the pics. This was another airline that appeared widely around the UK regionals in the 1980s often for the International Leisure Group (ILG) whose main tour company was Intasun at airports where ILG's own airline, Air Europe, did not operate.
ILG and Air Europe went bust in March 1991. I remember it well. I was on holiday in Spain with another carrier and tour operator when the immediate closure announcement was made.