I'm American so I've seen this in so many movies and just wondering, what's up with that? Example: We will not need those blankets in Russia-r.
Further to IMSoP’s answer: I live in a non-rhotic part of the UK. Non-rhotic means we don’t sound Rs *unless they’re followed by a vowel *. So we drop the R at the end of ‘rotor’ but sound it in ‘rotor and wing’. This has an odd result with all these words end in A: because ‘rotor’ and ‘rota’ sound the same to us, so do ‘China’ and ‘*chiner’. So we say ‘China’ just as you’d expect, but ‘China and Indian’ come out as ‘Chiner and India’.
I think there's a possibility here that you're listening with a rhotic ear to someone speaking with a non-rhotic variety.
Rhoticity doesn't just present as a different pronunciation, but also as a different perception: certain word pairs are homophones to a non-rhotic speaker, even when pronounced by a rhotic speaker.
As a non-rhotic speaker, I cannot distinguish between "rota" and "rotor", even if the person speaking has a rhotic accent and distinguishes them. So for all I know, when I say "rota", you would hear it as "rotor".
This is similar to the frequently parodied inability to distinguish "l" from "r" in speakers of many Asian languages. Often, they will appear to use the "wrong" consonant, since to them, the two consonants are indistinguishable.