War of Resistance: I Activate the Transmigration System and Hand It Over to the Nation

[Transmigration] + [Weapon Overmatch] + [Revenge]

Good news: I've bound myself to a System that lets me travel through time and space!

Bad news: The destination is fixed in 1937, a place filled with war and suffering.

Even worse: I rescued someone, and now the national security agency is after me.

What kind of firepower is this in 1937? Rocket launchers?

What was that flying across the sky over America? Alien technology?