Franklin D. Roosevelt was said to have been quite the charmer in his time. Mainly in the way he talked and ability to make people listen to him, some examples can be seen in sources of him on television and radio. It's said that though Hitler himself was a great person of charm, Roosevelt was the same, however not to the levels of the dictator. Roosevelt was the greater man and applied it with good terms, unlike Hitler. Also I heard how Adolf was the first to use a plane to travel while promoting himself politically, as with adoption of surrounding the area of where he talked with speakers. Maybe this would have contributed to the alluring of Hitler to the German people? 

All this information is from the top of my head, and I'd have no idea where to retrieve the sources in relation to it. Thankss