T7 flyer,
You may want to check those numbers. I believe its 280ish by 2020 at the moment. There are supposedly more aircraft leaving the fleet next year than what are being delivered. The last of the 777s now on order arrives in 2020. The 77x isn't available until after 2020. We have 100 777s now and will peak at 160 with present orders. So the FO with the last command on the last 777 to be delivered has been in the company for a few years by now. We have close to half of the 380s on order by the end of this year. The 350 (if they arrive) start in 2017.
The 4 year commands are over.
The Don