They do pay off for large congested airports with limited landing slots (e.g. Beijing between Guangzhou, which is the only 380 I’ve flown on). But this isn’t as much of a problem as we thought it would be 20 years ago. Incidentally, this used to be why Japan flew so many 747s on domestic routes.

Right, but in order for that to work you need to be able to consistently fill the planes to capacity. That's not as easy as it sounds. There's a limited number of routes where it makes sense, so that means you don't really have an economy of scale opportunity.

Yes, for sure. It makes sense on a few routes in china ATM but as airport infrastructure and high speed rail are built out, airbus is surely in trouble (same reason japan no longer uses any 747s domestically, and Boeing has basically relegated the 747 to a freighter, albeit a very successful one).

Funny thing is that the 747 was originally designed as an airframe that could convert to a freighter. That's why the cockpit is in a bubble above the main cylinder of the fuselage--to get out of the way of the cargo.

Back then, the conventional wisdom was that eventually all passenger travel would be supersonic. Boeing put their best folks on the SST project, and the 747 was a stopgap afterthought.

Turned out that fuel efficiency was way more important than speed.

The problem is that the A380 creates so much wake turbulence that the next aircraft has to take off a bit later, negating some (but not all) of the advantage!

That depends on whether you have enough A380s out of the airport you don't need to worry about wake separation so much (I imagine, despite never being there, that Dubai is like that at certain times of day!).

The success of the 747 was wrongly analyzed by Airbus: it was not successful because it was big, it was successful because it could fly further than anything else. It is however because it was big that it could fly far: if I remember correctly the fuel needed to fly grows with the surface of the plane (in 2 dimensions), while the fuel that can be hauled grows with its volume (in 3 dimensions).

The 777 had already made the 747 largely obsolete, and the kings of long haul flights going forward will be Boeing 787-9 and Airbus A350-900. With probably a mix of both in most long haul fleets.

It's surprising that Airbus did hit the jackpot with its A330, seemingly by accident, and yet seems to have been unable to foresee that it really was the future. Boeing built a better A330, called 787, and even though the A350 is a success, simply by virtue of being a larger plane that goes further it will probably not sell as much as the 787.

Also, up until relatively recently regulators wouldn't let twin engines fly transoceanic flights because they deemed it too risky. They added ETOPS[1] regulation in order to allow this

[1] https://en.wikipedia.org/wiki/ETOPS

Prior to this change you needed 3 or more engines to cross large bodies of water or ice. When ETOPS was revised the abbreviation was backronynmed to "Engines Turn Or Passengers Swim".

This is important, ETOPS regulation changes are a big reason twin jets are resurging

Yeah my understanding is that the 747 was a success because it could cross the major oceans in a single go, something smaller twin engines could not do at the time. This while providing a price pr seat that most people could accept.

Now we have twin engines that can at least do the Atlantic trip just as well, allowing all manner of smaller airlines to offer trips from a multitude of airports.

> Yeah my understanding is that the 747 was a success because it could cross the major oceans in a single go, something smaller twin engines could not do at the time.

Technically they could but regulations didn't allow it at the time: 1953 FAA regulations required that twin-engined aircrafts always be within 60mn of an airport, and ICAO had slightly less restrictive limits of 90mn. This meant some routes were entirely unfeasible, or the flight path required to keep within 60~90mn of an airport at all time made it uneconomically unfeasible.

3- and 4-engined aircrafts were not affected by these rules (starting in '64 for the 3-engined ones).

The rules started being relaxed in the mid-80s with the introduction of ETOPS ratings (initially 120 and 180, now up to 370).

This isn't about efficiency or cost per passenger mile I think.

The A380 was a bet that the hub and spoke model (where passengers travel to an airline's hub in small planes and onwards from there in larger ones like the A380) would continue to rule the industry.

Instead, what happened was low cost carriers flying passenger directly to the destinations. It appears that passengers prefers that, which is why the B797 and A350 exists.

The thing is, you can't fly big planes between small destinations because they will be half empty. Years ago planes weren't efficient enough to allow small planes to fly the long distances that are flown today. So, point to point is possible because planes are more efficient

> If there was a significant cost saving (there isn't) then of course it would make sense

There could have been, but Airbus shied-away from a really radical design like a blended-wing-body and stuck to traditional tube-and-wings design, just on a larger scale.

There's not much margin for efficiency improvement in that case other than begging the engine manufacturers to work more magic.