In 1987 I lived in Adelaide and with a friend I flew to Melbourne on the Thursday evening of the Adelaide F1 grand prix so lots of inbounds. The plane (an Ansett 727 I think) was empty apart from the two of us. After take off the CSM came and asked us what she could do for us. My friend immediately said “see how many gin and tonics you can get into us before we get to Melbourne” with which she duly complied. We somewhat staggered off the plane at MEL.
On an even earlier occasion (late 70s) we were in the US on a rugby tour. One of our players suffered a relatively minor injury but still had to return to the UK. He was BA cabin crew and he later recounted that he was the only passenger on the plane which was great. The downside was that they lost his baggage….