That's a great question. I haven't any idea how many years that gentleman worked, though. I do know there was a DL FA who recently celebrated her 55th with the company (she started with National back in 1958). In any event, I think the average worked is around 80 hours a month, though this may be pushing things; schedules for F/As and pilots can vary and some will choose to work more a month than others. However, let's just simplify things and use a more conservative figure of 75 hours a month. Using that same 450 mph figure as in my other calculation, that works out to 405,000 miles a year. Over a 55 year career, that would be 22,275,000 miles. Again, this is a bit of a simplification since someone flying 55 years ago would be back in the prop era when speeds were slower, but I think it's a decent approximation nonetheless.

However impressive this may be though, this is only hours flown while working. If someone's a commuter and/or frequently flies NRSA, it would be very easy to go significantly above that figure in total miles flown.