Airbus Retirement / Replacement Plans?
 

What is the current retirement timeline for the A319/320 fleet? Both average north of 20 years with 320s pushing 25...

Any talk of additional NB Airbus in the mix beyond the A321neo coming? Or replacing with more 73s?

Net loss of 3 planes this year with the delayed deliveries coming from Airbus. Next year is a much more aggressive delivery schedule, maybe a little bit of growth depending on the retirement schedule. As for why United isn't taking more deliveries, Airbus just couldn't deliver on SK aggressive delivery schedule needed for the NEXT plan, so most of the NEO's replace existing air frames to be retired and most of the XLR's replace the 757's. 737's will fill in the rest as needed.

tl;dr: This fleet isn't really going to grow much over the next 5 years compared to the 737 fleet.