F-18 E/F Super Hornet would be the easiest upgrade. Similar training, large commonalty in the spares pool so they've already got most of the logistics in place.... it'll be a low cost upgrade so...
It takes 14 hours to go from DC to Tokyo in a subsonic commercial airliner. Why would it take more than that to merely cross the ocean in a super-cruise military fighter?
30 years to mars? What, you think they'd drive there? It's 6-months.
10-abreast B777? I don't know where you got that information from. I was on a B777 last year and it was in a 3-3-3 configuration in coach.