There's an entire website devoted to this,
The site you mention is probably
this one. The lengths that some of the posters go to in revealing some error are really quite pathetic.
The problem with aircraft in films, particularly period films is obviously the availability of the right type and mark - take 1940 BB Spitfires for example. Add to this the director's own idea of what either he wants them to sound like, or what the viewing public think they should sound like.
Don't forget Hollywood's motto: "Never let reality get in the way"