Originally Posted by saturn

Well please consider: The oldest 319 hits 30 years old in 2029, and the youngest in 2033. Our younger batch 320s (Ships 3251-3278) will hit 30 years old between 2027-2033.
All 737-800s hit 30yrs old between 2027-2032, with the exception of the 6 ex-GOL. About 30 752s can make it to 2035 if they fly 34 years.

It was as if you were leaking some new development, but the expected and normal retirement timeframe for the 319/320s has always been the early 2030s as they come up for heavy checks at 30/34 year mark. Some jets can go through checks to 34 years to mass retire with the newer builds at 30yrs (see 757).

As for replacements, we rarely order new jets >5yrs out. The RFP for new NBs into the 2030s will need to cover 85 319/320s, 71 737-800s (likely all 77), 80 717s, ~60 752s, 16 753s. Thats 300+ jets. Many of our 220s/321neos will be here concurrently, to trickle out older 320s & 757s, and add growth. Who knows how many MAX aircraft we see by 2030 at this rate. There will need to be another big NB order to cover deliveries in the 2030-35 timeframe, likely with high numbers being taken per year. SAQ airport jets are niche, and any MAX8 would surely be evaluated as part of a much larger order. There's not much to choose from amongst the new gen products. (MAX8, 319/20neo, A221/3).