747 SP to Bahrain
Not Quantas, so maybe an aside, but one of my fondest memories of international air travel over 50 years was the non-stop flight from JFK to Bahrain on a Pan Am 747SP in 1977. As I recall, perhaps inaccurately, the flight took some 13 hours. The plane was half full, and I played cards with the "stewardesses" (they did not mind being called that in those days).