The most interesting Tim Clark's remarks are about the engine :
" To meet Emirates’ performance needs, the 777X’s GE9X will need a water-injection system to ensure that the aircraft can operate comfortably year-round from Dubai on all its required missions. “Unlike earlier demineralised water-injection systems such as on the BAC One-Eleven, this one is all about coolant – very high temperatures at high work rates,” says Clark.
“It makes a very material difference to our operating capabilities in the hot months in Dubai. Without that, the 777-9X doesn’t do that much better in those conditions than the -300ER does today.” "