Why doesn’t a twinjet double decker airplane exist?

Question

I read an article about the Airbus A380 (Let’s call it an A380 from now on) and why the production of A380s ended. The article cited 2 reasons for end of production of A380s: Point-to-point transit is more common in aviation nowadays, which didn’t make sense for me because, in reality, most airlines (With the exception of some budget airlines) use hub-and-spoke transit instead; And the fact that the A380 is a quadjet, which makes because twinjets are cheaper for airlines and ETOPS exist. With both the A380 and the Boeing 747 out of production, twinjets (The Airbus A350 and the Boeing 777X in particular) have taken over and they sadly, however, have only one deck, and that explains the title question. Sorry for the post being long

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Answer 1

Why *would* a double-decker twinjet exist? That’s actually two separate questions: why would you want a twinjet that big, and if you had one why would you want it to be a double-decker?

The latter question is pretty easy to answer…you only want two decks if you’re *huge*…A380 huge. 747 only has the partial upper deck for freighter reasons (because of when it was originally designed, the industry assumed passenger traffic would all end up on supersonics and the 747 would be relegated mostly to freighter life). If you take that partial upper deck away, you get a 777/A350. And the market has proven that, with capable point-to-point twins, there is very little demand for passenger aircraft that large…total fleet at that scale is under 500.

So we don’t want *any* airplane that big anymore, so no more double deckers regardless of whether they’re twins or not.

And, thanks to ETOPS, you don’t want more than two engines unless you need it for thrust reasons. But we’ve gotten better about aerodynamics so we haven’t needed a larger thrust engine than the GE90-115B, which was developed ~20 years ago. Even the largest new twins (A350-1000, 777-9) don’t need that much thrust because their aero and structure are so much better. No airplane of feasible size needs more than two engines anymore.