The 'Simple Flying' website is probably not the best source as IIRC it's been criticised on AFF for deficient research.
However a 6 May 2022 article was the only one I could quickly find estimating the supposed cost to QFi of operating return nonstop flights Sydney-London-Sydney.
The four year old (and hence dated) estimate was US$280,000 each way, which at 90 per cent occupancy 'Simple Flying' claimed would need QFi to receive an average of (presumably US$)1307 from each of 214 passengers to break even. Fares would need to be higher to cover the costs of security and other airport charges plus a possible fuel surcharge, as well as a margin for QFi.
At 2 August 2026 exchange rates, US$1307 equates to approximately A$1860 one way, so a return trip supposedly has to generate an average fare of A$3720 plus the items mentioned above.
The article was silent on freight revenue that contributes up to 30 per cent of revenue on some flights. QFi has said these flights will carry freight, though at what revenue per kilogram is unknown.
The article claimed fuel would be more than 50 per cent of the cost of operating each flight.
Has anyone access to a 2026, rather than 2022, likely cost and hence required revenue estimate?
Fuel cost depends on QF's hedging strategies, and whether Iran v Israel/USA and Russia/Ukraine wars continue.
My guess is QFi will make a reasonable profit from these flights with premium class passengers being 'fundies', CEOs of ASX-listed companies, highly paid entertainers and sportsmen, public servants on junkets and politicians who claim to be time poor, even though the time saving compared with using SQ, QR, JL, NH, EK, EY, MH, KE or others with efficient connections at their hubs isn't huge.