That's the thing. It hasn't been observed only in the US. There has been reports all over the world. It's just that the reports have been published more in the US than anywhere else. I mean the whole country went batshit crazy over UFOs in the 50's and had radio shows and movies and TV series. They capitalized on the subject. And people started interpreting everything they saw in the sky as UFOs. So maybe it's a little over reported there.

There's a lot of activity in South America, but it's just under reported. There's activity in Russia too, except their whole gouvernement works in total secrecy. And depending on the regions of the world, some being more religious might interpret these phenomena as divine manifestations so it won't be reported.

And like they said in the Congressional hearings, it happens way more often but there's a stigma associated with it and people are afraid to report if it means putting their jobs at risk.