What does Mamiya’s facial expression means when the other guy proposes to continue to where they left off?
Its an open ending so its up to your imagination. For me, especially Mamiya's facial reaction, I would say he'll refuse. They can't go back since they already have their own families. Humura just mess it up badly but also not his fault, we wasn't sure about his feelings towards Mamiya so he decided to end it all yet also regret it at the same time. (=・ω・=)
Inwoo travelled to where again? Is it true that the passengers would clap?
Russia
I’m from europe and people clap in our planes as well. At least back then when I used to fly a few times. (=・ω・=)