Many long flights, but love flying! Time passes quickly for me, as I sleep naturally, very well on a plane.
Don't know if question means non-stop or with transits.
For me longest non-stop was Seoul-London, 15half hours, over North Pole. Holiday.
Then London-Los Angeles, 15 hours. Holiday.
Los Angeles-London, 14half hours. Work for hubby, holiday for me.
With transits, longest, Cairo-Oz, 28hours. Holiday. Madrid-Oz. 26 hours. Holiday. Oz-London, 25 hours. Holiday. Oz-Mexico City. 20 hours. Work, then again, on Holiday.
Latest non-stop, Oz-Antartica. 11hours. Day trip!
Have done many other flights of between 3-10 hours. Mere 'pups' by comparison, to the 'biggies'!
Just adore being Up! Up! & Away!