Originally Posted by
cmd320
The reality is that at some point, someone is going to have to make a ~200-220 seat aircraft. It's by far the largest gap in the aircraft market and it's something that will eventually need to be filled. The big question is whether or not DL is going to be able to wait for that to happen. With the recent success rate of Airbus and Boeing launching new aircraft being quite poor, even if something were announced tomorrow (which it likely won't for a while at this point) I would give it about a zero % chance of being available in 2025 when the 767s are on the way out the door. The A321XLR, while fine for tertiary cities/routes like BOS-MAN, JFK-EDI, etc. isn't going to be enough aircraft to replace the 767 on most of the European network.
That's not entirely true. Someone doesn't "have" to make a 200-220 seat (multi-class) aircraft. There's a reason there is a hole in the market there.
The reason for this is there are natural efficiency points of single and dual aisle aircraft. This just has to do with seat space relative to aisle space relative to weight. A 7-abreast airplane is absolutely wonderful for passengers but terrible for airlines. You have to carry around significantly extra cross section for only a few more seats - the aisle space is "wasted". That wasted space means more structure (more weight) and a bigger cross section (more drag). Both of those mean more fuel and, therefore, more cost. And if you make them "stubbier" (ala 8-abreast A330/9-ish abreast 787) that helps the seat:floor ratio but doesn't fix your drag issue (big cross-section, stubby aircraft).
If a manufacturer makes one, it will almost certainly be an even further stretch of the A321 frame (the 737 would be tough to get that big due to clearance issues meaning smaller engines and tail strikes). The challenge here, of course, is that to make a true 200-220 multi-class aircraft would be a significant stretch. To get the range + extra weight + maintain good enough field performance may require another generation of engine tech to achieve (theoretically, a niche aircraft that only works on long runways and no high and hot airports is potentially possible with today's engine tech).