The Yugoslav holiday flights had several advantages over those to Spain etc. They appeared to do no night flights, and for the UK at least operated almost wholly on Saturdays/Sundays. Commonly run as a "W" arrangement in a day, from Pula or Dubrovnik to a UK point, then to the opposite resort, and the reverse in the afternoon. I recall three Aviogenex Tu134A at manchester in 1980, side by side on remote stands, with the crew all out and chatting together. In uniform, but no ties ... unprecedented for UK crews in 1980 ! I believe all crews were ex-Yugoslav air force.