Out: On November 28 1984, Boeing began deliveries of the second generation of the legendary 737. The first customer of the new aircraft, the 737-300? US Air, as it was then called. (Piedmont Airlines would take its 737-300 in April 1985.) The 737-300 era at US Airways is now coming to an end. The last of the 124-seat planes will soon to be retired from revenue service by the airline — they’re already out of the schedule but I suppose could still be used as a fill-in for a short period to come. The larger 737-400 — which seats 144 for US Airways and for which Piedmont was the first customer back in 1988 — are still being flown by US Airways but in ever declining numbers. All should be gone from the airlines fleet within about two years or so.

In, eventually, in some form, maybe: Presuming it doesn’t merge with American Airlines, the next big thing for US Airways is the A350, Airbus’ next generation of widebody jet. Airbus is currently planning to build the A350 in versions (lengths): the base -900, which will be introduced first, a stretch -1000, and a shortened -800. The -900, which is an Airbus A330-300 and A340-300 and Boeing 777-200ER replacement, is selling well. The -800 is, however, having issues. Qatar Airways and Libya’s Afriqiyah Airways have recently converted their -800s orders to -900s, cutting the -800 order book from 118 to 92. There’s widespread industry speculation that the -800 will either be delayed, cancelled outright, or redesigned for improved efficiency.

US Airways is tied with Aeroflot as the largest remaining customers for the -800; both have 18 -800 and four -900 on order. US Airway’s 22 A350s are currently due between 2017 and 2019 with 10 being replacements for its old Boeing 767-200ERs. The airline may also choose to use A350s to replace its 9 A330-300, which will be 20 years old by then. The other remaining A350-800 customers are Aircraft Fleet Purchase (12), Asiana Airlines (8 plus 12-900 and 10 -1000), AWAS (2), Hawaiian Airlines (6), ILFC (6 plus 14 -900), Kingfisher (5), Libyan Airlines (4), Tunis Air (3), and Yemenia Yemen Airlines (10). There’s not a lot there — the leasers (AFP, ILFC, AWAS) can and will jump to other types if the -800 continues to struggle for sales, Asiana and Aeroflot could also easily convert to the -900, while Kingfisher is pretty nearly bankrupt.

There are a lot of ways this can turn out, depending upon what Airbus and US Airways choose to do. A conversion by US Airways to other Airbus types is a distinct possibility. I don’t pretend to know what will happen, but however it turns out it will greatly effect the airline’s intercontinental operations.