"Having movies made about you does not an icon make''.
But it certainly helps! Being an icon is as much about public perception as anything else. I would say that the most ''iconic'' figure was Bader. If they were all up stage on a reality TV show called "Pilot Idol" then he would probably win.
Now if they had asked "who was the most singnificant'' it would mean something else completely. I believe they had actually meant to ask us that, but due the the celebrity culture we now live in, they had to use a modern journalistic phrase.
I treated the question as "significant'' and voted for Dowding. Because without his insight and organisation, we would have lost the Battle of Britain and would all be speaking German now.