The real question is can United wait until 2025 at the earliest to replace the 757 fleet. The answer is no.
Why? Are the airframes closing in on their hours/cycles fatigue limits?
They’re hangar queens. The reliability of the 757 and 767 fleet is not good. The 753 fleet is especially bad.
757s are having to go into lower utilization duty from everything I'm hearing. A great airframe when new. They age less gracefully than the 737NG as the NG was improved much more to help it.
Both have subsystems that are great for 7 years, a little more troublesome until 14 years, and then a pain. The subsystems lack any chips to help diagnose upcoming issue (R&R prior to a missed flight). This means more backup aircraft. That is cheap (due to the fact the aircraft are paid off), but as oil rises, it is time to replace.
By -10MAX or A321NEO for domestic/Hawaii. Perhaps the A321LR for TATL?
Some can make it to 2025, but there is a reason UA wanted new build 767s as a stop gap (but at a price/delivery pace that Boeing couldn't meet).
This is an old link comparing the 757 to *proposed* aircraft. Please note fuel is at only $1.60 per gallon in that study (versus today's ~$2.15). https://www.iata.org/publications/econo ... index.aspx
But the basics are correct. The 757 is a dog for maintenance and fuel burn.http://www.aircraft-commerce.com/sample ... sample.pdf
When I recalculate based on expected NEO/MAX maintenance, today's fuel price, and today's lease/finance costs.
I arrive at -10MAX at 95% of the cost per passenger of the 757, but that gap is growing due to bad 757 aging.
A321 at 95.5% of the cost per passenger of the 757. The higher cost per passenger entirely driven by the fact the A321 is selling for more than the -10MAX. Range has a value...
Higher utilization of an A321neo or max increases the cost advantage due to very low variable costs.
The best examle is JetBlue plans to use the A220s 12 hours+ per day because they have such low variable costs!
Winter is coming.