I have been fortunate with two "Bests", and to date no significant "Worst" airline experience.
Best 1:
Very late December 1965, and booked on British United Gatwick to Guernsey with my wife and our 10 day old daughter, to spend Christmas in the family home in St Peter Port with my wife's parents, and to have our baby baptised in the island. Our flight by Viscount was cancelled because of excessive crosswinds at Guernsey airport, and our happy plans were ruined. On explaining our plight to the BUA airport staff, they were marvellous. They had us immediately transferred to a BAC 1-11 flight to Jersey, which was about to depart, our bags were whisked into the jet, and we were conducted out to the aircraft, which we boarded up the rear fitted stairs to find all passengers already seated
and facing backwards! It was one of BUA's troop-carrying aircraft, which at that time the MoD required to have "safer" rear-facing seats. So my daughter's very first flight was made to the wrong island, and backwards! We were put up overnight in a very comfortable St Helier hotel at the airline's expense, and flown the next morning in a Dakota to Guernsey. We had a splendid Christmas, and our daughter was christened on Boxing Day in the parish church (yes, really!). I almost wept, when BUA eventually went bust.
Best 2:
Mid 1980s, travelling by BA in a 747 to Bahrain in business class, (up the spiral staircase into the "hump"), at the expense of our client needing a structural problem sorted at Sitra power station. Being well before 9/11, I asked politely for a cockpit visit, and got it. Got chatting for ages to the 3 flight crew, including various navigation systems, and the friendly captain enthusiastically demonstrated how he had loaded the INS panel with the necessary data prior to departure. Did give me an odd feeling that maybe the large number of paying passengers might not have been too happy that the captain, F/O and engineer were all nattering away to a stranger, rather than paying a bit more attention to the task of flying the big beast. My ignorance, of course, half-expecting at least one of the pilots to be gimlet-eyed and constantly gazing ahead like Biggles ... I then made the mistake of mentioning Decca Navigator systems (one of our structural clients), which set the F/O off on a long reminiscence of when he had used their "moving map" device back in his days in the service. I greatly enjoyed my prolonged chat in the "office", although when I went back to my seat I did wonder if it was possible that all the button-pressing in his INS demo by the captain might have had some unwanted effect on our arrival in the right place! It didn't of course, they were obviously competent professionals.