Thanks for raising this topic BigDog.
A few years ago my Dad in his early 60s was rushed to intensive care with a pulmonary embolism after a 4-hour flight to the Canaries.
He is under 6′, never smoked and has always been active.
Obviously underlying conditions play a significant role, but when are airlines going to learn?
For example, 3-4-3 on a B777 is just not on.