Range versus payload — the trade nobody advertises

Every quoted range figure hides an assumption about how much the aircraft is carrying, because fuel and payload draw on the same weight allowance. Fill the seats and the hold, and there is less allowance left for fuel — so the aircraft cannot fly as far. Fill the tanks instead, and something has to come out of the cabin.

Manufacturers describe this with a payload-range diagram: a chart whose line falls away as range increases. Airlines live on that curve. It is why a route can be flown eastbound but not westbound against the jet stream, why some long flights block out the last rows of seats, and why an aircraft advertised at 15,000 km may only manage that with a modest load.

So when this site quotes a range, it quotes the manufacturer's figure at a stated payload, and says which one. A range number without a payload attached is marketing, not engineering.