Age has everything to do with it. At 51 I looked at the CAL list last year and had to go something 150 numbers to find someone older than me and then another 150 to find another. I looked at the bottom of the CAL list yesterday now that it is full of United furloughees and I was slightly over the median age. If you place a younger pilot hired after an older one ahead of the older one, the older pilot will never advance to where he would have(career expectation). If on the other hand you place the older pilot hired before the younger one ahead of the younger one then the older pilot will still end up where he would have and the younger one will end up where he would have. The younger pilots career may be delayed, but that is made up for by the fact that he will have much greater opportunities to advance to a wide body captain as United has two and a half times the number.