Dreamland(2007)

In the Nevada mountains between Las Vegas and Reno in the desolate nuclear testing grounds of Dreamland (Area 51), a young couple Megan and Dylan stop in a greasy spoon cafe where they learn about the Area 51 government base a few miles away. After they get back on the road, Dylan turns on the radio. The only broadcast he can find is a speech from Adolf Hitler at the 1936 Olympic Games. The car dies and a visitor appears from another moment in time. When Megan and Dylan look closely they realize that it is Hitler from the past.