spent his time dealing with schedule changes, calling the trade and private passengers to tell them the flight times had been changed, sometimes significantly. I guess that the intention was to chop any weak rotations and keep the load factors way up by smart utilization.
This was how charter operators worked in those days. Not only consolidating loads in the shoulder season to keep any flying seats sat on, but also mixing it with late charter opportunities, in particular chances of subcharters to other operators where needed, firing off to do such a sudden lucrative operation and then coming back maybe hours late for previously planned work.
"Hello, um, we're AOG at Malaga awaiting an engine change with 150 return pax in the terminal. You don't have nearby by any chance ..." "Oh YES we do ... where did you say it was ?"
The worst were the US transatlantic charter companies, who by the 1970s-80s had mainly moved on to Stretched DC8s. They would take commercial arrangements, but their base load was US military charters to Germany etc, which inevitably would often get switched around at the last moment. This was a lot of unbalanced work and the commercial charters, having positioned back from Frankfurt to Gatwick or wherever, were a way of getting loads both ways. Actually changing the day, even for return flights of a US charter group back home, were not unknown. It was generally palmed off as "technical issue needed for safety" rather than "commercial department got another opportunity".