here is a route-specific question that I've always been curious about --
An LAX-SYD flight is a big moneymaker because fares are high, and it carries a lot of valuable cargo. However, the fuel loads are huge, and the aircraft sit on the ground in SYD for probably 8 hours.
Would it be possible for such flights to take a stop in HNL, so that the fuel load/burn could be reduced by more than say, 1/3 on each leg, as well as cargo load increased / money saved? I have asked various experts about the extra time taken to make a landing/takeoff in HNL, and it seems to be kind of complicated, needing to factor in ascent/descent times, ATC routing, etc. But given the leeway in the schedule, if the savings in fuel could translate into savings in fare, maybe this would be attractive? Of course, everyone wants non-stop routings, but just out of curiosity.
Perhaps there are crew time limits that come into play also, but do you have any thoughts on this?
I think your question slipped through the cracks so I'll take a stab at it.
First of all, it wouldn't necessarily be a crew scheduling issue. That's a managable issue.
You're bringing back memories from my old aircraft performance classes from University. You're right in that as manufacturers build longer and longer range aircraft, inefficiencies start to come into play and compromises start to be made. It costs the designer, and therefore the airline and ultimately the consumer money to carry the extra fuel required for that 14th hour of flight because the aircraft has to carry that fuel load (i.e. weight) for 13 hours! The designer also has to now build a larger aircraft that is structurally "sound" enough to carry all that weight in fuel and overcome all the stresses required for normal flight. So now we're talking more mass, which requires more fuel to stay airborne. So as designers build longer and longer range aircraft, if you're looking at absolute cost as far as aircraft design is concerned, there is a point where it becomes cheaper (in term of fuel costs) to divide a flight into 2 segments using shorter range aircraft rather than one long range aircraft and the inherent inefficiencies in such a design.
So the question becomes, do we, as consumers of long range aircraft, want cheaper tickets or is our time more valuable? The guy shelling out the big bucks for that first class seat from Hong Kong to the U.S. probably thinks his time is more valuable, so the airlines give him what he wants and he pays a premium for it and the airline earns a disproportionate profit from people like him. So as long as there are people willing to pay a premium for a non-stop service, the airlines will give it to him. Maybe as fuel gets more and more expensive consumer behavior will change, but right now new international non-stop city pairs seems to be all the rage.