Did not rtfa, but I would guess private jets.almost exclusively. Air travel even in a traditional passenger jet is incredibly carbon intense, even splitting the emissions by 300 or so.
So a) they travel by air far more than avergae, and b) they’re doing so in private aircraft.
But we could also rtfa.
edit: saw the original ?toot?. there is no fa. but there was another figure that confirmed, it’s yachts. not even planes. mfing yachts. How much yachting can you possibly be doing as an individual to make that size of a carbon footprint?