Well I guess the wing span really matters, but ... we can always go to other airports ... anyway we always go to big ones ..
Turns out it is connected to weight as well.
A330, B777-200 and others have MTOW of 230+ tons. A310 and B767 are in 164...179 ton range.
Which may affect trip costs, airport charges etc. etc.
I'm leaning in to telling him to go for a slightly smaller one and just stop in the middle and change the crew, it really sounds better than just keep going forever. A regular 75 will do the job just fine and it will make him look good too. (It's all about looking good)
A regular 757-200 has nominal range of 7200 km - with commercial payload and without extra tanks. Which means slightly over 8 hours endurance. You still have to carry extra crew and have crew rest - and in 757-200, hopefully there is space for it.
And in 767-200ER, too.