Originally Posted by
carrotjuice
Interesting that you’re required to stay on board at MXP enroute to BCN, whereas you must disembark at MAN enroute to IAH, or at HKG enroute to SFO.
Likewise for BA must disembark at SIN enroute to SYD.
Different airports, different countries, different regulations.
I’m pretty sure there’s some DHS requirement for security checks before the aircraft departs for the US, if the local airport doesn’t already require that for through passengers.