As for the US bias..

..as we know, the US govt spends a lot of money on military hardware and experimental weapons and aircraft. Plus, the media there beats everything up out of proportion. Plus there's a lot of people not that well educated to make sense enough of what they might be seeing. Plus there's active disinformation campaigns going on all the time. A bunch of reasons contribute toward the US bias, but there are baffling cases all over the planet.