hold on, what kind of emissions attribution is happening to make business class travel less CO2-efficient than economy class travel?? your ass weighs the same no matter which chair you sit in
@whitequark I'm not entirely clear on how these things are computed, but I kinda assume they have to be assigning everyone some amortized portion of the cost to fly the plane empty? and like, if there was less demand for a given class, they'd fly planes with less of that class, which potentially means smaller planes
@whitequark and removing a row of business gets you a lot closer to the next-size-smaller plane (with lighter fuselage, lower fuel burn per mile, etc) than removing a row of economy, and it also potentially allows you to fly more people on the same fuselage by adding more economy, which reduces the per-passenger fuel burn…
@rcombs hm, is it actually the case that smaller planes have lower fuel burn per mile? that doesn't make sense to me. why even have big planes if so
@whitequark @rcombs Presumably larger planes have higher fuel burn per mile and lower fuel burn per mile per passenger.
@whitequark if it wasn't true, why even have small planes? any given plane is most efficient per-passenger-mile when flown close to 100% load-factor
a smaller version of the same plane (same engines, avionics, etc) has lower dry weight and will cost less to fly empty
on the other hand, flying 1 big plane is usually more efficient than flying 2 planes that are half the size, because the 1 big plane has less dry weight than the 2 small ones (and costs that are fixed regardless of size, related to eg drag and takeoff/landing, would be increased in the 2-small-planes case)
@whitequark @rcombs it's going to depend a lot on what engines are on the plane, but in general bigger airframes have bigger engines and bigger engines use more fuel
they don't necessarily use proportionately more fuel, though; in absolute terms a bigger engine uses more fuel, but it produces more thrust, that additional thrust means it can carry more weight, and that means more passengers and cargo. if the increase in revenue from passengers and cargo outweighs the increase in costs from fuel, it makes sense to use the larger plane
or in other words, if both a larger plane and smaller plane can carry your passenger and cargo load, the smaller one is likely to be more economical (but this is a really complicated discussion because it needs to consider things like flight time, fuel burn per hour, what cruising altitude each plane has...)
@demize @whitequark I'm largely setting aside differences in the engines themselves in favor of assuming they're mostly going to be similarly efficient in their design deployments these days, but compare eg: a 737 MAX 10 carries ~33% more passengers than a MAX 7, has ~12% more MTOW, and has 72% more cargo space, but weighs ~13% more empty; same engines
those numbers pretty clearly add up to "the bigger one is more efficient on more-popular routes, while the smaller one is more efficient on less-popular ones"
@whitequark @mcc I mean, if the counterfactuals are "fly 2 planes" and "fly the big plane half-empty" respectively, then they absolutely can both be true, just in different situations