What Ollie said.Mothra vs Rocketeer is a tough one, even given the obvious scale difference. Both have heroism and the power of goodness going for them, and both can actually fly; Rocketeer would at least be able to stay in the fight for quite a bit. I think ultimately Rocketeer's lack of Kaiju-damaging firepower would mean he couldn't do much against Mothra. Afterwards, they'd recognize they are on the same side and go kick some nazi ass, of course.
Or basically just any movie where Kaijus wreck the Nazi's shit.