Which commercial aircraft, when fully loaded with fuel (and passengers and luggage up to its max takeoff weight), could stay in the air the longest without landing, and how long could it stay in the air? What conditions would it need to have maximum possible endurance if the plane had no intended destination to land or particular flight path? (This is for a fictional story.)
Note: I was thinking commercial jetliners when I wrote that, and I still am, but I was accidentally unclear about it. That's preferably what I'm looking for, though.