I think CPZ reserves 10% of its positions for "lifers" to claim (and giving up the right to flow in the process) but I'm not sure how that works once the flows are completed. CPZ is growing, and I don't see why the flow down wouldn't apply to all CPZ positions regardless how big they get, but I'm not 100% sure how that works.

Flow downs keep up to 2 years of their DL longevity in the left seat of CPZ or 4 years in the right for CPZ pay table purposes.

It would be very expensive to dump and flush the entire CPZ list on a rolling basis up and down. The cost of doing so is one of the best defenses against a furlough.

Of course that doesn't seem very likely at this point. We are very "efficient" and productive compared to the last time the industry went in that direction, and we have a lot of retirements coming up starting in just a couple years.

At this point I'd say 1500 is absolutely safe (thermo nuclear world war or asteroids the size of Texas notwithstanding, etc) and pretty soon 1000 will be just as safe, with the likelyhood of even 1 being on the streets lower than at any time in the history of the industry. Still possible in some scenarios, but very unlikely.