Well see here's the thing ... the sherrif of nottingham (no prizes for this one) came from nottingham.
Robin hood on the other hand, well he came from barnsdale - between barnsley and doncaster - he lived, fought and died in yorkshire - and so is in fact a yorkshire man!
As for the airport - the doncaster sheffield kind of locates the airport - but it is a clever piece of marketing don't you think?