American airlines don't buy new planes. Third-world airplanes buy new airplanes and once they've taken depreciation for them they sell them to American airlines. Even if they quit making new 737s, Southwest could be still flying old 737s 40 years from now.
It's tempting to say that some of the worst airports in the US (say Newark) are "third-world" but the truth is that a bad airport in the third world is often a lot better than any airport in the U.S.
This prof was talking about defects in the last generation 737
-- Southwest orders 150 737 MAX airplanes and 58 Next-Generation 737s
-- Southwest becomes launch customer; scheduled to take first 737 MAX delivery
-- Largest firm order in Boeing history
Since then, they operate 223 of the 737 MAX (16% of deliveries) and have 495 on order, which is about 10% of total orders. At a single airline. United has 159 and has 388 on order. Then comes Ryanair with 136 delivered and 374 ordered. These are not third world airlines.
It's tempting to say that some of the worst airports in the US (say Newark) are "third-world" but the truth is that a bad airport in the third world is often a lot better than any airport in the U.S.
This prof was talking about defects in the last generation 737
https://www.ithaca.com/news/cornell-expert-boeing-737-plane-...