It was not uncommon in the 1970s/80s for return Greek islands flights to need to make a fuel stop on the return, the usual combination of runway length/temperature/etc putting a nonstop out of range - though Med resorts by definition don't get hit with altitude. I think even 707s could get hit from the shorter runways.
Brindisi was a favourite, they must have had cheap fuel, and/or landing fees, and/or a handling agent who got it all done in short order. It was not a IT flight destination but must have picked up quite a bit from tech stops. It seems only 110 nm from Corfu to Brindisi so there's the efficiency in not going all the way up to altitude and back down again. I wonder if from the mountains of one you can see the mountains of the other.
Here on Youtube is someone's video of a Laker One-Eleven arriving at Corfu in those times. Don't look at it taxying if you work in Health & Safety !