Boom Overture, which does not yet exist, is supposed to have a range of 4,250 nm (presuming they can get their engines to actually exist, which is a giant quest

Boom Overture, which does not yet exist, is supposed to have a range of 4,250 nm (presuming they can get their engines to actually exist, which is a giant question-mark). That means they can bring JFK-FRA into service, but SFO-SIN is going to be tight even on just one refueling stop (7340 nm but the jet stream is working against you the entire way- sometimes it will require a second refueling stop!).