The 1968 "Where Eagles Dare" bugged me the very first time I saw it (I was 10, it was on TV in the 1970's) when I saw a Bell 47 posing as a WWII German helicopter. The historical accuracy crew phoned that one in... Otherwise it's a passable film, among the better of the latter 1960's WWII fare...
... and this video is blocked outside of the US why? Hardly seems to be a military secret any more. No matter, a much longer and more detailed account can be found here: