Payload
Pool,You are absolutely right - it's about PAYLOAD. An a/c manufacturer builds the airframe and the airline decides what to carry in it. Everything they decide to carry in it is PAYLOAD - be it Pax, Freight, Showers, Bars, Comfy Seats, etc.In the case of the A380 ALL the airline customers to date have decided to carry a lot of weight (payload) to provide luxury. They could decide (and may do so in the future) to bin the luxury and configure the a/c like EK's B777-300. The TOW and Fuel Burn will be almost unchanged (all those seats, showers, bars add up to a lot of Pax believe me), but the Fuel per seat numbers will be transformed.As also noted in this tread the economics of a streched A380-900 (the a/c is already designed for such a stretch) will be another step change - if/when Airbus can afford/be persuaded to launch such an a/c. B777-300 vs A380-900 will be no contest - but we should expect that - there is the size and technology difference playing in the A380's favour.